Model Engine Maker

Engines => Your Own Design => Topic started by: AlexS on January 21, 2018, 12:12:43 PM

Title: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 21, 2018, 12:12:43 PM
Hello, this is my building log of first and own design combustion engine. For several months I am busy with building of the engine.

My goal is to make the engine block as solid as possible. So that is one of the reasons that it is big stroker. The engine should have the possibilities to be able to easily adjust.

The swept-volume is 55 cc, with a boring of 39 mm and 46 mm stroke. I want it to run at low to mid range. So let's say 750-3000 rpm.
Intake valve diameter 18 mm with a max lift of 4.5 mm, exhaust valve diameter 14 mm and a max lift of 3.5 mm.
One camshaft fitted two cams that are adjustable. The duration of the cams would be around 200 degrees, I have to go into this further.

I want to make most of the parts by myself. But given that this is my first engine, I also use existing components. Such as piston, valve springs and a spark plug.


Feel free to give comments!
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 21, 2018, 12:29:54 PM
First I had to turn a new flange to mount a four claw chuck for my lathe. With my current three-claw I can not turn large diameters of rod material.

Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 21, 2018, 12:37:20 PM
Start building with some raw material. First part, crankshaft crank cheeks.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 21, 2018, 12:43:15 PM
Cylinder head. I try to upload photos chronologically as possible, but as wel all of one part.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 21, 2018, 12:49:11 PM
The diameter for the valve seat of the inlet has unfortunately been larger to 20 mm. Due to a measurement error (x-as movement). :-X
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 21, 2018, 12:53:07 PM
Cylinder
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 21, 2018, 12:56:23 PM
Drill holes for mounting on cylinder head and crankcase.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Ramon Wilson on January 21, 2018, 01:37:40 PM
By my engine building standards Alex that's one big engine - ten times bigger in fact  :o

That's some nice machining you are doing there - I'll look forward to seeing it progress in coming days

Regards - Tug
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 21, 2018, 01:43:56 PM
Thank you Tug, yeah the reason I want to make a bigger one is the diameter of a standard piston. And the ability to use some larger parts for valve stems etc (round 5 mm). The photos that now are uploaded are from a month of two ago. Recently I had solder the exhaust valve.

I want to upload more, but for some reason it didn't work. Maybe I had to wait some time ;)
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: scc on January 21, 2018, 01:47:08 PM
Looks an interesting engine. I'm following along too :popcorn:   Keep posting.    Regards       Terry
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: b.lindsey on January 21, 2018, 06:57:24 PM
Also following your progress Alex.  Nice documentation of the parts so far.

Bill
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Plani on January 21, 2018, 08:07:06 PM
Interesting Build! Keep the pictures comig  ;) :popcorn:

Plani
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 21, 2018, 10:03:57 PM
Connecting rod and small-end assembly. I had the idea to fit a 15 mm outside diameter for the small-end bearing. But unfortunately there are no 15 mm drill or cutter. :noidea:

Because of that, I have made a part of material C45 to fit the bearing.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 21, 2018, 10:12:55 PM
First (rough) work on the carter. Plates  are 6 mm. The squired profiles are 20x20. On the left and right side there would be a plate of polycarbonate, to look inside the engine (if you can see something with running the engine full of oil ;).
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on January 26, 2018, 08:00:56 PM
An interesting build  :ThumbsUp: Larger than I can do with my machines. There is a lot of experimentation possible with camshafts, valves etc.  :wine1:
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Art K on January 26, 2018, 09:55:52 PM
Alex,
Wanted to let you know I'm following along. It's also a bit larger than my Val at 1.125 X 1.1 inch bore & stroke. Are you intending to use splash lube? If so seal it well with silicone and it should be all right. Good progress, look forward to the rest as it progresses.
Art
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Allen Smithee on January 27, 2018, 12:18:44 AM
May I ask why you've chosen to have the exhaust valve smaller than the inlet valve? I would normally expect it to be the other way around.

AS
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 28, 2018, 07:19:27 PM
Thank you all. Roger, my lathe isn't very big one, but with some hint and tricks it is good possible to make a larger engine. I am amazed that the lathe engine continues to rotate larger diameters and harder metals. While the electric motor only has an eighth horsepower of power and some 1.6 Nm torque.

At the moment bottom part is almost finished and I am busy with making valves and seats. Later this week I will upload a little more of the progression.

Art, splash lube is a good idea. But I had in mind to use an existing oil pump. From here I planned to build a pipeline that could lubricate the big end and the cylinder wall as well as possible. But I am open to suggestions. What is the best way to design a splash lube? And yes I want to seal the whole carter with silicone, and add two seals for the axles (15 mm).

Allen, there are two reasons why the exhaust and lift are smaller than the inlet. You want that the engine could breathe easily, that is called the volumetric efficiency. The intake air-fuel mixture is coming in the combustion chamber with a low temperature and pressure. But for the exhaust, the gasses leave the chamber with way more higher temperature and pressure. Because when the exhaust start to open, for a short moment the exhaust gases leave the combustion chamber with tremendous speed. Then the piston moving upward and pushed the rest of the gasses and ensure that the new mixture enter the chamber.
In view of this, the speed and density of intake and exhaust gasses aren't the same. So they needed a different opening to leave the combustion room.

Secondly you don't want a large exhaust valve with also larger mass. The main reason for the size difference is to avoid pre-ignition and knocking. Against that knocking will not be so problematic with a compression ratio of 6:1. But the exhaust valve is the hottest part of the engine. We also know that Q=m Cv dT.
Hence the heat generated is directly proportional to the mass of the substance. Now if the size of the exhaust valve increases, its mass increases. So the heat of the valve increases.

Now after the exhaust stroke, the charge(air and fuel) is sucked in for the next cycle. If the temperature of the exhaust is very high it may cause pre ignition.
Also even if the temperature of the valve is not that high, during compression the charge becomes more volatile. The exhaust valve will ignite the charge creating a flame front which progresses in all directions. Also the spark plug creates a flame front. When these two flame fronts meet, knocking takes place.
To avoid these difficulties the exhaust valve size is kept smaller than the inlet valve. Correct me if I'm wrong.

Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 31, 2018, 01:09:21 PM
Here some big update from the progress of December-January to today!

Crank pin journals with fitting an big end Ø 20 mm x 14.

Left and right main journals Ø 15. For the journals, I have milled some flattened piece in certain places. This to better fix the flywheel, distribution gear and oil pump later on.

Last picture shows two extra weights (4.7 gram) for the counterweight. This to fully balanced the rotary forces of the crankshaft and connecting rod assembly.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 31, 2018, 01:29:37 PM
A couple of main bearing 'blocks'. Each fitted with a 6202 bearing.

Then the crankshaft press assembly. Had to make a tool to mount the crank cheeks in parallel. The result was just fine!
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 31, 2018, 01:43:26 PM
Crankcase progress to fit crankshaft assembly! Need more adjustment in the future to run it smoother. But it is fine for now;)

Added some spacers for the mounting plate for timing belt rollers and flywheel support bearing. The hole to fit the main journals in the front and rear crankcase plates, are 25 mm. This to put some seals for the journals.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 31, 2018, 02:07:34 PM
Now it is more serious work! Valves and valve seats.

Valve stem of round 5. And the valve dish of staff material round 35 (needed for cams).

Third picture shows the result of solder at my home, but this was not good enough (heat to solder brass). So I had to do this with an autogenous welding machine set. I was lucky they had such a set at school. I thought the result was fine, for the first time I soldered hard (with some nice help tips from the workshop teacher !).
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 31, 2018, 02:16:43 PM
Modify valve disks. Before I install the valve seats in the head. I adjust the passage of the inlet in the cylinder head.

The seats and valves fits great so far. What a birth! This was done yesterday. Now need to fit some valve springs, camshaft assembly etc etc.

Alex
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 31, 2018, 02:38:41 PM
As an attachment you see a section of the cylinder head with valves assembly.

In red the connection between cylinder head and valve stem is shown. In blue, the connection between cylinder head and valve stem guide bushes is shown.

For the exhaust, the valve stem guide bushes fits nicely. But for the intake they are way to lose.
I had expected the milled hole to be small enough. I thought to make some sort of assembly bus. Where the bearings can be mounted more tightly. Outside diameter 10 and inside 7 mm.

Another thing is that the valve stem and the connection between the cylinder head has some slipstick-effect. Simpel solution would be to make the diameter in the head slightly larger. But I don't want that the exhaust gasses flow directly along the valve stem. Possibly I could make a guide bus for this. Maybe have someone any suggestions?
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on January 31, 2018, 03:46:43 PM
Two thoughts:

1. Are you sure that hard soldering will be sufficient for the valve heads, especially the exhaust valve? I have made my valves in one piece from stainless steel screws.

2. I have used one piece bronze valve guides with the outside diameter the same as the port.

Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on January 31, 2018, 07:43:29 PM
Roger, the temperature of soldering is around 900 degrees Celsius. For exhaust valve it might been critical. After some research on the internet, I saw that average the inlet valve would run around with 425-540 degrees Celsius and the exhaust 650-780 degrees Celsius. But this engine is not going to deliver high power and peak temperature.

I saw this method from youtube, so I give it a try. But your way of making a valve of a stainless steel screw is also great idea! I think it will be good enough for the first tests. But thanks! Maybe in the future I will turn out of one piece of material. For now I used material silver steel (115CrV3 I guess?), it can be hardened to 64 HRC.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Admiral_dk on January 31, 2018, 08:02:03 PM
The red area in your drawing looks like a problem area to me - but you might get away with it in a low power engine.

Good full size practice dictates that the valve guides ends either flush or a few millimetres inside the port / channel and inside the spring at the other end. This gives you a big enough support area for the valve stem. The clearance between the two are measured in um (micro-meters) - most of my bikes has been in the 25-55um for the inlet and 40-70um for the exhaust valve.
The engine will run with a much bigger clearance and I don't expect this kind of tolerance on a model we make - but the size of the tolerance has great influence on oil consumption if you have splash lubrication of the valves ....

The reason I don't like the red areas are heating of the valves and the cylinder head on the exhaust side and more wobble of the valves - but again, probably not a serious problem here.

Best wishes

Per
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Perry on January 31, 2018, 08:27:06 PM
Hi Alex, that will be big engine, will you try to power something with it once finished? (bicycle perhaps)
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on February 02, 2018, 03:56:36 PM
Per, indeed the red areas could possibly cause problems if the valves get really hot. But what you said, it won't be a high power en fast running engine. For the inlet, I have fit in some extra tube to fix the guide bushes better(shown pic. 1). And I had to make the red area slightly wider. I didn't measured the clearance between the stem and bushes, but now for both stems moves nicely. Fifth picture shows the valve assembly fit in the head with two springs. Lock the valve spring with a seeger ring 55 mm. I do not expect any serious problems, maybe I should make a firmer clip.

The spring constant is 3.63 N/mm. Reduced mass of valve train would be around 100 grams. So the own frequency of the spring with the mass would be around the 4000 rpm. This is higher than the max rpm what I would be running this engine. The spring length when the valves are closed are 8 mm. And for the intake 8+4.5 mm. Forces are not that high (29 N closed, 45.5 N opened), but I think it would be good enough to run it with low rpm range. The cam followers are carried out with rollers. With this and that it does not have to transfer many forces, I think it would be not that necessary to splash lubrication. Occasional greasing with ball bearing grease seems sufficient. Is not that right?

Perry, I have many this in mind to upgrade and to adjust etc. But first I want it that it run good with as a stationary machine. Later on I would make a hydro dyno (load cell), added some sensors like temperature speed etc. I have ideas to advance a programmable (mechanical interaction) ignition. In addition, maybe a throttle controller. Going to nearby convenience store with powered your own build engine to get some beer would be a dream! Maybe to attach this engine to a gearbox of a chinees motorcycle or a Puch moped engine in the future.
But this will come later! First plan is to start the engine properly;)
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on February 02, 2018, 04:01:45 PM
Yesterday started making the mounting beam of the camshaft composition. Two ball bearings 608 would be mounted in this beam. The intake cam comes to the left of the beam and the exhaust cam on the right. Also, two pairs of adjusting blocks are mounted on this beam where the valve clearance can be adjusted.  :cheers:
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on February 15, 2018, 01:15:57 PM
I am almost ready to start making the camshafts.

Does anyone have hits tips to make these on a milling machine with an indexing table? I was thinking to do it like shown in the first picture (blue square is the cutter)

The camshafts are mounted on an axle. The pics shows the intake and exhaust dimension. For the intake I want a duration of +- 200 degrees. This due to run the engine at low rpm. But as you can see in the first picture, with this geometry there is a duration of 272 degrees (136 *2). And for the exhaust the duration is 238 degrees (119*2). The third picture shows the valve timing. Here you can see that for the intake a late closing angle is chosen (for a small valve overlap with the exhaust).

What is the best way to reduce this duration (especially for the intake)? Increase the diameter of the circular arc to lets say 10-12 mm? Or applying a ridge with hollow flanks?
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on February 15, 2018, 02:38:03 PM
I have milled my camshafts using a table of lifts at 6° intervals. The tables were generated using the cam calculator on the Model Engine News website:

http://modelenginenews.org/

Go to Resources and then Design Centre. I'm not sure how compatible this is with the latest operating systems. Others on this site have also written similar programs which they are willing to share.

The cam blank was held in a simple fixture with a 60 tooth gear for indexing. The lift values were set using a DTI under the milling head. I have attached the table I used for the camshaft on my horizontal engine.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Art K on February 16, 2018, 01:04:01 AM
Alex,
My suggestion would be to use this program.
http://www.modelenginenews.org/design/CamTable.html (http://www.modelenginenews.org/design/CamTable.html)
You use an end mill and a rotary table. You zero the Z axis on the base diameter of the cam, mill across the Y axis then move the table up and down as the table tells you. Just fill out the parameters and it gives you a Z height for every degree increment. I did mine in 2 degree and it was ready to run that way, that also means 180 passes for each cam lobe. But there is no filing sanding ect.
Art
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on February 16, 2018, 09:58:15 AM
Roger and Art. Thanks for your information and explanation!  :ThumbsUp: Tonight or tomorrow I look after this.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on July 06, 2018, 08:18:42 PM
Hello guys, it has been a while since I gave an update. But in the meantime, the engine has already made a few plops! I had some 'problems' (challenges ;)) with sealing the valves for example (Now 5 bar pressure when turning the engine, had to say that the theoretical compression ratio has been increased duo to thinner Head gasket, so 1:6->7). But I am currently having a question about the crankshaft.

The crankshaft is currently split up. The cheeks are made of aluminum. This was a guess as to whether this went well with the drive shafts and pigtail pen of C45. I have found out that this is a bit of a success. Provided you turn a smaller diameter on the shaft for 'searching' the hole during pressing. But the squareness I did only afterwards. The squareness of the holes for the drive shafts are not good. Both drive shafts do not run in each other's center line. In other words, no straight crankshaft. You also notice this when you mount the block and turn around. It is a little more difficult with some strokes and you can see the drive axles swinging a little bit.
All in all, I think this is enough to start him.
But in addition, I have found out, as soon as he tries to start, that the drive shaft is rotated in the axle. This was fixed with a reasonable fixed fit. This can of course be remedied by the use of glue / or the installation of locking pins.

I am thinking to tackle the total crank cheek problem. So I want to make the cheeks of steel. At the moment I have a leftover cast iron. I wonder if this is strong enough? Given that the material is brittle. However, the material is easy to machine. And I'm probably going to use glue as a deposit (locktite 4xx, I do not know my number).
Or is it advisable to use another type of steel such as C45?

Soon I would upload some more pics and talk. Greetz Alex
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on July 06, 2018, 08:27:45 PM
First picture of the first test. It was pointed and quite messy in the R & D section! Here I found out that the engine contains too little compression.

The second photo is recently after disassembling the second test session.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on July 07, 2018, 11:34:09 AM
Today do some bit of math!  :smokin2: Cast iron can not handle the theoretical bending forces. Gas force is 4.8 Kn (ideal situation of combustion 100% VE). The safety factor is 0.7 ish (compared with 1.3 for aluminum and 2.3 for C45) with taking into account the jump load factor.
Cast iron GG25 is weaker than 2020. C45 would be ideal. But, you will not end up balancing the weight of the crank (rotating balance). It is possible, but then it is necessary to build a steel connecting rod. Maybe for another time.

Now I want to adjust the current crankshaft. The insertion of fitting sleeves to improve the squareness of the fitting of the respective shafts in the crank cheeks.
The new confiscation can be seen in the image below.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on July 12, 2018, 05:45:02 PM
The bending forces on an IC engine crankshaft are quite high. I have made my bigger ones from C45k with the balance weights bolted on. I think that getting a good bond between steel shafts and aluminium webs will be quite difficult. RC in Luxembourg do some useful sizes of C45k

https://www.rc-machines.com/en/materials/steel/flat/c45k

Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Admiral_dk on July 12, 2018, 09:22:43 PM
Your engine is big enough to get into trouble with the distance between crank webs and the bearings ....
Since it looks like the bearings are in separate holders (might be problematic too) I hope that you just can turn them 180 degrees or swap left with right side and get the bearings almost flush with the webs - this should stiffen the crank quite a bit ....

I got absolutely no experience nor ever seen a crank with alu webs, so my next comment might not be worth much, but ..:
Removing material from alu webs will not give you much, but putting heavy metal into the opposite position should be enough to balance the crank.

Best wishes

Per
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on July 18, 2018, 02:39:08 PM
Thank you gentlemen for your reactions! Meanwhile I have been busy fixing the aluminum handle cheeks on the crankshaft.
For me it was also questionable whether it would work. You can take a gamble anyway! The main reason was that I had no experience of milling harder metals. In addition, the use of aluminum ensures less oscillating vibrations. With an aluminum crankshaft and connecting rod it was possible to balance the crankshaft (rotating balance).

But! Last Monday the engine ran a few minutes !! And still pretty neatly stationary.
But unfortunately the locking(pins) of the cranks has been released. I doesn't have put some fitting sleeves in the crank. Now I intend to make the crutches, and possibly the connecting rod, of C45. I collected this material yesterday at a local machining shop.

First, before I go into detail, I chronologically upload the progress of the past months.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on July 18, 2018, 03:21:36 PM
In the month of March the components were made for the rocker arm / camshaft assembly.

The first series of images are the assembly and adjustment blocks of the tumblers. Now the valve clearance can be adjusted per valve. The axes on which the tumblers rotate are currently glued(locktite 402). But this can be replaced by a threaded rod by mounting both blocks. The valve stem lengths are almost identical. And the valve stem caps can be adjusted to the play (added later).

The tumblers are equipped with rollers. These are admittedly of softer steel than the silver-steel cams. For now the use of ball bearing grease for lubrication is sufficient.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Ye-Ole Steam Dude on July 18, 2018, 03:37:33 PM
Hi AlexS,

Beautiful design engine, will follow along.

Have a great day,
Thomas
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on July 18, 2018, 03:39:01 PM
Time to make some tools! A mounting block for fixing a three claw on the index table. The indextable is mainly used for milling the cams.

The three-claw is fixed with the 3 original bolts of my lathe. Given that you can only mount bolts on one side. Did I use three imbus bolts as centering on the indextable side. In addition, the whole is mounted by means of a threaded rod that you tighten through the middle.

The whole has done a nice job. However, the span was large. For the milling of the cams it was advisable to also manufacture a countercenter. This naturally resulted in fewer vibrations.
I like to make some useful tools.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on July 18, 2018, 03:39:52 PM
Thank you Thomas! I appreciate it.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on July 18, 2018, 07:05:58 PM
Some nice work there  :ThumbsUp:  :ThumbsUp: I am not sure that the aluminium crankshaft webs will work due to the different stiffness (Youngs Modulus). The webs will less stiff than the shafts which will tend to make the holes in the webs barrel shaped.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on July 19, 2018, 05:39:14 PM
You are right Roger. I am currently working on making steel crankshaft webs.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 09, 2018, 09:57:52 PM
It has been a while since the last update. First a series of photos of the engine components for the first start session (July).

First set of pics shows the milling of the cams on the index table. The cams are locked on an aluminum turned tool (Not so well visible in the photo). This was done by placing a pin. As a guarantee I glued both the cams and the locking pin.
In the small tool, a inbus needed to be fitted on one side. This inbus was mounted against one of the three claws, this prevented the tool and thus also the cam from turning during milling.

I don't have more pics of milling the cams. Sorry.

To fix the cams on the engine, I did have drilled and tapped a hole through the cams and the accompanying shaft. Then the cams are fitted with the use of a set screw and glue. Meanwhile, I started the engine a number of times. And the fixture remains very good.

Also you can see the timing belt assembly. Fitted with four 608 bearings as span and fixed roller. Timing belt T5x10 total length 550 mm. Number of teeth of the pulley are 20 and 40.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 09, 2018, 10:34:40 PM
After machining the cams it was needed to make a flywheel.

It is desirable that it has a relatively large mass inertia. However, I am limited to the maximum diameter of around 130 mm. In addition, a wider flywheel would take the center of gravity of the total engine too far out of the center.
The flywheel diameter 120 mm, around 1.5 kilogram.
Speed variation is theoretically acceptable for this kind of engine. Starting from the requested torque of 2 Nm, the speed variation at low revolutions (750 rpm) is Cf 0.11 (85 rpm) and at high revs (3k rpm) Cf 0.01 (21 rpm).

I have taken a piece of residual waste from a local turning and milling shop. On both sides of this writing it was sawn off obliquely. This took some time to get this on one side at right angles (1-2 hour ish :D). Then I turned the piece of metal around and turned the actual flywheel. Given that there was already a hole in the metal, I installed an aluminum core. With the core fitted, it was able to support the piece of metal with a center for less vibration for turning.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 09, 2018, 11:02:32 PM
Back to modify the head. Fitting a spark plug. First determine the desired distance and lightly drill with a center drill. Then setup the angle of 45 degree. The use of a center drill and big enough drills works quite well. After that the hole were tapped with M10x1.0.

The fifth photo shows the inlet manifold. In the photo you can see that there is a slot in milled for the carb.
The carburetor is made of orgine for 2t machines (Rc / chainsaws). It concerns a Chinese brother of a zama C1Q. In view of the operation of the carburetor, the intake of fresh petrol through the inlet and the exhaust pulses of the crankcase of the orgine two-stroke engine. However, this appears to work well with a four stroke engine so far. Given this reason, a slot is milled in the intake manifold.

The diameter of the carburetor's passage is 14 inside and 13 mm outside if I'm not mistaken.

Last picture shows the head gasket made of copper-alu alloy. 0.6 mm thick. So th. compression ratio is increased from 6:1 to 6.9:1
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 09, 2018, 11:29:55 PM
Back in June, first ignition sparks flying around! Use a Rcexl set ignition but not with a CM6 spark. Had to add an extra ground for the better spark. Power the ignion system with a usb 230v power supply. Work great for now;)

Next serie of pics shows the modify of the exhaust valve seat. First test session in begin July shows that the engine has low compression. Biggest problem was the seal between the exhaust valve and the seat. The concentrically of both parts was not correct 0.1 mm ish. With adding some water and use of pressed air it was easily shown here it was coming from.
Had to fit the head in the chunk of the lathe. So that said, that done. I did use the tool that I early made for drilling holes in the cylinder. Tapped 4 M6 in it to fix head on it. At the position of the valve stem I used a long threaded end to clamp it in the lathe. I had to use a valve spring to reduce the vibrations of the threaded rod.  ;)

So sealing checked, and it was at the same level as the inlet valve! Use for both valve polishing paste for automotive usage.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 10, 2018, 10:41:23 AM
Adjusting the aluminum crankshaft (try to safe it). Use of an additional fitting bush and fixing the crank pin. This job also done for make the crankshaft more concentric and straight.
These changes I applied for the first start of the engine.
But at the end it did not help for long, given this reason I started to make a steel crank.

https://www.youtube.com/watch?v=iW1OjxQKsvw
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 10, 2018, 10:41:46 AM
Video shows the first real run of the engine! :D This was when the engine run with the aluminium crank webs.

https://www.youtube.com/watch?v=AjQ59ooyb68
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 10, 2018, 10:57:12 AM
Creating a new set of crackwebs made of C45. No need to make a steel connecting rod to compromise the extra weight of the webs. Images shows the section view of the engine and two of the theoretical rotating mass balancing. One part of the connecting rod would be defined as 'rotated mass' and the other half as 'oscillating' mass. For this reason, about half a conrod has been drawn.
The different between center of mass and the center of the crankwebs are minimal.

Maybe I will add once two or four balance shafts to balance the whole together (for compensation the oscillating mass).
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 10, 2018, 11:31:55 AM
The next series of photos shows the making of the steel crankshaft. The milling of the handle cheeks took the most time. The milling machine became hot quite quickly. Matter of manufacturing with an occasional break.

For one of the crank web I have turned to the final size of the diameter of the driveshaft, so that I can fit driveshaft of the flywheel side. And also modify the diameter of the driveshaft and crank pin, ready to fit in together.
The last thing to do is to eventually turn the diameter of the other drive shaft. The crankshaft is already mounted with the connecting rod. It was important that the connecting rod with an elastic was mounted on a fixed place (wall of the shop), to prevent the connecting rod from swinging around in the lathe.   ::)

Last step was pressing the last drive shaft in the crank cheek and welding the entire crankshaft. This is to prevent the drive shafts from turning in the crank webs. It was necessary to align the entire crankshaft after welding. It was a bit exciting, but after my say, it succeeded.  :DrinkPint:

https://www.youtube.com/watch?v=p-H130ptQB8
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 10, 2018, 12:02:56 PM
Second test session with the new steel crankshaft. Engine looks solid, and need some more love for ignition/fuel tuning!  :DrinkPint:

Pics shows build up. Add some liquid gasket on the bottom crankcase and two shaft seals on the drive shafts to prepare for the use of an oil in the crankcase.



Things I want to do are:

Add a left and right crankcase plates, a crankcase blend nipple for adding oil in the engine. First I try to use splash lube, I had some ideas about a oil pump, but that can be done later.

Make a better mounting block for the ignition pickup, so changing time would be easier to do.

An extra support block of the camshaft assembly (for less deflection of the camshaft by tightening the distribution belt).

Exhaust manifold and exhaust pipe/muffler. Thing is 'pretty' loud! (On the advice of the neighbors)

Making plans and sketches for the dynamo meter / sensors. Later on I would start an different topic about this.

And other stuff to modify / adjust.


https://www.youtube.com/watch?v=wv_RPuoKGlE
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on October 10, 2018, 12:14:07 PM
You've made a lot of progress  :praise2:  :praise2: It runs well  :ThumbsUp: Are you triggering the ignition from the crankshaft? The RCxcel units have a built in advance curve which is designed for this.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 10, 2018, 10:55:22 PM
Thank you Roger. Yes the ignition is triggering from the crankshaft (mouthing a magnet on the flywheel). Don't know of the advance curve is acceptable for the engine. Maybe good to mount a stroboscope between ignition and plug!
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 08, 2019, 09:23:26 PM
Long time ago. Times flies when you're having fun/bussy/working??


Quick update. Last Juni a upgrade to the engine and a start and tune.



First pics view of piston and cylinder before update run. So after rebuild with steel crankshaft. Running fuel + 2t oil.


I added a extra support block with bearing to prevent bending of the camshaft. This allows to add more tension to the timing belt.

As you can guess, the previous camshaft was broken after add some pressure to the timing belt when the engine was running. So this stiffen the camshaft drive train some bit.

When remaking the stock shaft to mount both cams, I did changed the lobe degree between the two camshafts to get some 'better' valve timing. I did checked the timing on opening and closing degrees. The intake duration is okay, some ~200+ degree and exhaust ~180, I don't have my notes here.
So I did add some lobe degree to get the opening timing of the exhaust some bit sooner.

In the video you can see that the engine is now equipped with transparent poly carbonate plates. This allowed the crankcase to be filled with 300cc of 10W40 oil. Added a crank ventilation and filling holes.

Next time I will make a new exhaust and maybe intake cam with more duration(now with consideration of the difference between theoretical and measured duration). , And make no mistake with to small diameter and so sharp exhaust cam, I really don't know how I did make the exhaust diameter of stock material smaller  :-[ :-X
Also I will build the support shaft of the cams out of round bar without retaining groves to prevent axial movement of this shaft. I think these groves again caused a break in the described support shaft.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 08, 2019, 09:24:05 PM
Video of run Juni

https://www.youtube.com/watch?v=SFQC0DZZyjE
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on October 09, 2019, 10:07:13 AM
Good to see you back on this one  :) There was less splashing in the crankcase than I expected.

Did you reduce the base circle in your cam design to allow for the valve clearance? This can be responsible for some loss of opening angle.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Brian Rupnow on October 10, 2019, 01:43:50 PM
I admire your support tower for the camshaft and how the rockers act directly on the valves. Nice design, nice engine.---Brian
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 14, 2019, 06:46:00 PM
Thanks guys!

First try with oil was 300 ml ish. But this gave too much splashing oil in the crankcase. Such that at higher revs a reasonable amount of oil came out of the crankcase ventilation hole (no pcv valve/hose for now).
Get some oil out so there the crankshaft barely touch the oil bath. And modified valve timing (lobe degree) to compensate the very very unusual opening time of the exhaust valve. I think this caused 'some' pressure in the carter, because old timing openend the exhaust after bodem dead center ;)

The base circle of the exhaust cam should be the same as the intake. But with milling the profile I had milled off too much. So this also result to more exhaust valve clearance than intake. But valve clearance was easy to modified, by make the hole bigger  mounting block of the exhaust rocker assembly. Next time exhaust should be the same base circle as intake (15 mm instead of 13.16 mm).

Recently I have written down all notes and adjustments of the latest tests. This also applies to the valve timings and clearances.

Timing first starts with old camshaft axis.

- Intake
Valve Clearance: 0.6 mm
Valve lift: 4.1 mm (4.7 mm - 0.6 valve clearance)

Opening: 28 BTDC
Closing: 8 BBDC
Duration: 200 deg

- Exhaust
Valve Clearance: 0.5 mm
Valve lift: 3.83 mm (4.33 mm - 0.5 valve clearance should be 3.7-0.2)

Opening: 28 ABDC
Closing: 19 ATDC
Duration: 171 deg

Valve overlay: 47 deg

Lobe separation angle: 128.5 deg





Second timing. Goal to run with current cams but trying to get some early opening timing of both valves.

- Intake
Valve Clearance: 0.2 mm (minimum)
Valve lift: 4.5 mm (4.7 mm - 0.2 valve clearance)

Opening: 1 ATDC
Closing: 34 ABDC
Duration: 213 deg

- Exhaust
Valve Clearance: 0.3 mm
Valve lift: 4.03 mm (4.33 mm - 0.3 valve clearance should be 3.7-0.2)

Opening: 13 BBDC
Closing: 2 ATDC
Duration 195 deg

Valve overlay: 1 deg

Lobe separation angle: 100 deg



For next timing I will try to make an adjustment of the lobe degree to get a duration (with valve clearance in mind) for both cams around 220 deg. And opening intake and closing exhaust around 10 deg. Should be 20 deg valve overlap enough for low-mid rpm performance?

Compression test old camshaft and without oil in crankcase: 5 bar. Latest camshaft 9.77 bar.


Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Admiral_dk on October 15, 2019, 11:48:11 AM
First, nice runner  :cheers:

You are right about the conrod only skimming the top of the oil is more that enough - just look at bearing tables, where the max RPM is a lot higher in a oil mist condition compared to oil bath.

I would had said that your first valve clearance values were much too high, as all my four-stroke bike over the years has between 0.08 and 0.15mm. in cold condition. Clearance in this area depends partly on materials and partly on dimentions, geometry and temperature range.

I'm no expert on this subject, but I would expect that the ideal clearance results in somewhere around 0.001-0.01mm. at max working temperature.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 15, 2019, 04:50:47 PM
Thanks for input Admiral. I would check what a reasonable valve clearance would be for this engine, I see no big expansions but be sure that valves not openend duo to not 100% round base circle of cams.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Art K on October 15, 2019, 06:50:22 PM
Alex,
I'm on vacation and just caught up on your build. Good job getting your own design running. :ThumbsUp: I saw the earlier video with the free standing cam with unsupported ends and made a mental note. I would have supported both ends but it obviously works quite well now that the cam is supported. My experience with crankcase splash lube is that to much oil without proper crankcase ventilation causes it to come out EVERYWHERE. Very messy.
Art
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on October 15, 2019, 07:51:27 PM
Thanks Art, I agree with the messy part of to much oil. The engine did get lubricated on the inside, but also on the outside.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Art K on October 16, 2019, 01:56:49 AM
Alex
I can laugh with you on that one! :lolb:
Art
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on December 24, 2019, 11:11:33 PM
I saw that the reason for breaking the camshaft axle (support the cams) had to do with some not true 90 deg bored hole in the camshaft support tower.
Two years ago I did bore this hole on a machine at school. I did not notice it before and it was no problem before I added the extra 3rd support bearing with block.
On side to side there was 5 mm (!) difference.
Luckily I could bored to 24.5mm and reamed to 25 at work.

Today I made for this a bearing block to mount the two 608zz bearings. Fitted well and now nearly 90 degree fitment and inline with 3rd support bearing.

Made a drawing of the second version of the exhaust cam. With 0.2mm valve lash in mind to have a duration of ~220 deg instead of 195 and 3.5 mm lift. Coming soon.

After that new camshaft axle. Addition in mind to mill the upper carter surface of compared to camshaft support tower for better mounting and looking of this assembly.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on January 01, 2020, 08:25:25 AM
Glad that you spotted and corrected that problem  :)  :ThumbsUp: It would have caused you a lot of future problems  :toilet_claw:
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on April 25, 2020, 02:27:53 PM
Yes indeed Roger. Currently I am busy with building a test station to fit the engine. So that I can test it outside + dc fan + gasoline tank. I would show more upgrades of this engine on this forum.

Alex
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on April 25, 2020, 06:22:29 PM
Building and testing is always fun and a good learning experience  :ThumbsUp:  :ThumbsUp:  :wine1:
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on August 06, 2021, 08:10:09 PM
Progress and testing from last 1.5 year!

Photo 1. New exhaust cam, now with cam lift 3.5mm and more duration than previous (less sharp edge on cam lobe). Later on welded on camshaft same as intake cam.


Modification of the camshaft pulley to fit a 8mm locking assembly. This to be sure no rotational movement and easy adjustment of camshaft timing! Photo 2 and total assembly at photo 5, here you can see that there is also a locking assembly fitted in the flywheel.
Big upgrade, because flywheel rotated a bit after quick acceleration of the engine and moved ignition timing. Also now easy fitting of flywheel.

Photo 3. For in the future driving a dynometer (work in progress :) or something else, a pulley is needed to fit the output shaft. Also here fitting a locking assembly 15mm for 8M 20 timing chain.

For better and tunable ignition timing a pickup plate has been made. So now you can fix that Chinese hall sensor better on the engine! Timing can now quick been modified around 15 degrees. Another option is to lose the locking assembly of the flywheel to set the base ignition timing. This shown in photo 4 and 5 (difficult to see, see next assembly pictures).
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on August 06, 2021, 08:23:54 PM
Testing the engine shows that it pops quit hard and so a large force caused to bend the top plate of the crankcase. This cylinder is mounted to the top plate but the middle part is not fixed to be stiff enough.

So there is an crankcase reinforcement been made. Photo 1, 2, 3 shows the extra beams to fix the top plate better to the rest of the crankcase. As you can see the beams are different, because in the top plate two extra holes are made. One hole for oil input and the other for fixing an crankcase breather (the breather showed later on).


The crankcase is now more solid. Now to the next upgrade. First the crankshaft axial movement was blocked by two circlips. But they did not resist the force and is not best way to do I discover later (same as making cuts in shaft for weak spots).
To prevent to much movement, axial bushes/bearings do the job. Aluminium pieces to set the crank right in the middle of the crankcase. Job done.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on August 06, 2021, 08:29:09 PM
It is nice to have oil in an engine. And it is nicer to stay in the engine :old:

So to realise this, a crankcase breather was born. The little breather come to earth quit easy and do the trick with some foam inside it. There is still a little bit oil leakage, but only between cylinder bore and top plate of crankcase. Only needed to modified cylinder for a O-ring. On the to do list!
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on August 06, 2021, 08:42:39 PM
The engine wants some damping.

And exhaust has been made. All from stainless steel that I have laying around.

Total exhaust volume 125cc factor 2.3 of the engine displacement. 8 mm inlet and outlet diameter. 18 mm silencer expansion pipe, 37 mm inside diameter of the silencer. Holes has been bored in the expansion pipe of 2 and 3.5mm. Damping wool used to fill the silencer.

The engine produce now nice and quiet sound!

Photo 6 shows also the crankcase breather located on the top plate.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on August 06, 2021, 09:01:46 PM
Last week been working on these upgrades. head bolt reinforcement and testing stiffer valve springs.

First two photo's shows the head bolt reinforcement. In the past winter I did long run test the engine. After the test I saw a crack from the weak spot of the cylinder head. I guess thermal expansion of the aluminium head did this, shame on you aluminium, the head bolt can't beat it so caused to much stress.

To avoid this further, the following came up. Placing metal filler bushes. These are placed in the head and now the cooling fin is not loaded with tightening of the head. Especially when it gets hotter.

Also on photo 1 you can see for the intake a added isolation plate. To prevent heating carb and to connect crankcase pulses to pull fuel to the carburettor (copper pipes / hose). No more starvation.



Someone at youtube advice me to try stiffer valve springs. Good idea! So fitted today stainless springs with a springrate of 8.1 N/mm instead of original 3.6 N/mm.
The springs are 24mm long instead of 27 but added minimum seat force of 50 N instead of 35 N. Max force with lift now 85 N, before 48 N.
Also have a pair of steel ones with springrate 9.8 for testing later. Photo 3 for spring comparison.


Last photo shows "new" "fuel tank" with fuel usage test. This with new valve springs today. Engine running stationary around 1000 ish rpm for more than a half hour.
Fuel usage around 100 ml test, so 200 ml/hour for stationary no load.



Now I have no video of up to date engine, but one with exhaust modification. Hope you have enjoyed the update greets Alex.

https://www.youtube.com/watch?v=xji_OSKoH2g
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on August 08, 2021, 08:04:46 AM
That seems to be running well  :ThumbsUp:  :ThumbsUp:  :)

How is the test bed/dyno coming on?
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on August 08, 2021, 03:12:31 PM
Thanks Roger!

Beginning of this year working on first constructions of the test bed and dyno setup. Now on hold, for other hobby 2t expansion chamber project going on.

Idea to feeding 5v or 12v dc pwm % voltage though a 230v 500W motor for acting like a eddy current brake. Quick test seems working.

Already build the base and sub frame roughly. Need to modified the mounting parts for the motor. To be continued! ;)
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Vixen on August 08, 2021, 07:36:38 PM
Hello AlexS

I like the way your engine is running, I think the see-through crankcase is a great idea. You can see much more of the action.

Mike
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on August 09, 2021, 04:46:34 PM
Yes true Mike! Also good to see check the amount of oil splash to check and oil level.

Am also thinking to add one primary balance shaft just for trying to get less vibrations for low speed.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: propforward on August 09, 2021, 05:53:58 PM
 :ThumbsUp: :ThumbsUp: :ThumbsUp:

That's a really well made engine - runs superbly!
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on August 13, 2021, 11:25:52 AM
Thank you Propforward!
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on September 20, 2022, 11:08:51 PM
So. Work on motorcycle almost done, steady only small things. Lets play again with this stroker.


From a friend he working with old M50 Puch's, I got a spare 15mm Bing carburetor. Let's try if it makes a difference between the first chainsaw 13mm carb. Making a quick adapter to fit this Bing. After couple of test results that it could run stationary and full throttle. On the + side, much less fuel residue that sticks through the inlet than the first chainsaw type.

So I looked for a small four stroke carb that has tunable airscrew and no electric choke (modern scooters GY6 sizes 16mm+). Now I know the difference more between 2 stroke and 4 stroke carbs. Really need bleed type needle jets, or at least that airscrew adjust mixture in needle. Maybe 2 stroke reed valve carb is better for 4 stroke than port type barrels.

But found a 9mm carb that originally fitted on a small Honda Monkey, Novio, Amigo, PC50, PS50. Main jet tunable, airscrew, jet needle adjustable, great great!
Order also the smallest jet of size 50 (0.5 mm??) and 80.
It came with a unknown and unnumbered jet.

It just fired up  like a couple of cows that are allowed to go back to the meadow after a long winter. brap brap brap.

The fuel tank version 1 (old 500ml coca cola bottle from 2018) and version 2 (beer bottle Leffe from 2021 (great beer)) doesn't work well with this kind of carburetors.
And version 3 was born in the middle of the night. From a small cute Spa water bottle. Now with a hole in the cap, than on the bottom of the bottle. Not ideal in terms of leakages etc etc.

So after that a serious fuel tank has been drawn from sketch! Version 4, had to be Heavy Duty stainless steel 304 or 316 got it from work. 3mm thick. So TIG welded. Bore some holes, weld a couple of M6 thread ends to fit a Puch 3-way fuel crane and Heavy Duty banana bracket (I know I did enjoyed TIG welding to long).

It is just great. No leakage and workarounds any more. Fit the job, done.



Now it was possible to test with certainty that the carburettor was getting petrol.
Changed the original jet for the smallest 50 size. Run the engine warm and find the highest running speed on the airscrew (around 1 to1.1/2 turn). Choke work well, need some time to warm up.

Able to check and tune ignition time better. Did some adjustment of moving the magnet position by unlocking and locking the flywheel locking assembly. And fine tuning the timing is possible to turn the hall sensor pickup.
Static ignition timing now 25 deg BTDC, dynamic stationary around 15 deg half full to full speed 35 deg (measured by stroboscope). Just perfect. Maybe some fine tune to 10 degree.

Starting and fire. Testing with to much advance popped out the silencer of the exhaust muffler. I was testing in the dark to see the timing light. Shock me to death. Thing hit the roof. Now TIG welded to rest of muffler.

Compression after run feels low. I know barrel is not perfect straight. Compression test shows 6.5 bar. And that with 7:1 ish compression ratio. If I remember right, it was cold +- 8:1.


Currently thinking and drawing some upgrades for this engine.

Ah, almost forget to tell about dyno test center. Last year I builded the dyno (electro motor) with frame etc. Result engine could not start with the load of belts and turning motor. When loosing belts it was with old carb hard to rev a little bit before loading the engine. Thinking of, when time is right adjust the test center to flywheel type dyno. Future future! :)

Alex


https://www.youtube.com/watch?v=gqxP4fjMYYs

Video shows run with stiffer valve springs, on camera it looks odd to see cam and tumbler motion ;p
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on September 21, 2022, 05:39:42 PM
Planned upgrades or modifications

Trying to make the engine more suitable for stationary or moderate speed load work.

- Quit a bit of oscillation vibration. Two first order balance shafts spur gear driven. Was thinking to balance also the second order. But these shafts need quit a bit of space. And fully balancing the first order take 77% of total unbalance force. Would talk about later about this.

- Oil sealing of the cylinder. After running the engine under quit a bit rpm it tend to leak between the crankcase top plate and cylinder bore. Easy modification would be use of o-ring or maybe sealant.

- Sparkplug and cold start exhaust shows burn of oil. It depends on the level height of the oil splash lubrication. Current cylinder bored in 2017 with the tools and methods available, I do know it is not straight but okay for running!

- Cylinder and maybe head cooling. Designing new wet lined cylinder bore pressed in aluminium. I'm thinking of choosing his own motor oil as a cooling medium, lubricate and prevent corrosion the cooling channels and tubes. A small rotor oil pump (forget name of the 5 rotor) to push the oil around the engine to a pc radiator (or maybe own build).

Thinking of two options of lubrication with new oil pump. There should be a oil tank under the engine crankcase or have to look if it fits the current crankcase. If using a tank under the engine. I was wondering if you can use it as a dry sump. Oil pumped to the cylinder and the liner has some small holes that feed a little bit of oil to the piston skirt (when piston is on BDC) and if piston moves upwards it would spray on the crankshaft and connecting rod. The motion of the crank would if right swing to the cylinder liner and bottom piston.
Other option is to stay with the splash lubrication tank or no tank. If tank then it is possible to place an overflow pipe (vertical) in the crankcase where the oil level of the crankcase is fixed.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Admiral_dk on September 21, 2022, 07:05:31 PM
Great to see that you have been having fun with your build  :ThumbsUp:

Oiling - oh yes - so many options ....
My old Gixer (GSX-R1100H) had Air/Oil Cooling (inspired by an old US War-Bird) ....
It worked fantastic - as long as the Oil Temperature stayed under 110C (above that it started to drink Oil).
The other end of the scale, was Husquarnas first Four-Stroke Racing bike - No Oil-Pump at all ....
The OHC for instance was lubed by the Oil that the Chain pulled along from the Crank-Sprocket and up to the Cam-Sprocket. Here most of it was 'Flung-Off' and catched by a specially formed shape in the Head and ran through a bore down to the Cam-Bearings and the Lobes + Valve-Guides. After doing it's duties in the Cylinderhead - it ran back down to the bottom again.

Hope to see more from you again   :cheers:

Per
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on September 21, 2022, 09:59:40 PM
Great Suz you had, like the bodywork and headlights of the late 80 and 90 Suzuki's, especially the Srad with there round butt.

This new cylinder should also have a mix of air and oil cooling. Interesting way of transporting oil of that Husky engine, is that there first four stroke enduro/motocross engine?

To control temperature of oil/engine idea to mount pc fans and controlled by on off cycle or maybe side project arduino pwm control.

Of controlling oil pressure, I think need a sort of reducer/checkvalve that can be adjusted by spring ratio or setup depth.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Admiral_dk on September 21, 2022, 10:59:10 PM
That old Gixer will in many ways always be the best bike I ever will own  :Love:
But I had to give her up - my lower Back, didn't stay bendy enough ....
I had to start ending my Holigan ways of riding (it was my first bike after a very serious accident and I had her for 8.5 years) .... I kind of knew my luck / skills wouldn't last forever (43yrs then) + I started riding Off-Road (for slow recreation and scenery).
I'm sure that my trusty 2004 DL650 (1st. owner) will outlive her by decades and keep me entertained - but in Looks and Exileration - there is NO comparison ...!!!!

It was absolutely Not Husquarnas first Racing Engine - at some point they where considered the Best MotoCross Racing bikes (all two-stroke @ the time) and participated in other forms of racing, RR etc.
But as far as remember reading back when I saw the Four-Stroke MotoCross from them - the article said it was their first Four-Stroke.
The argument (and Sales-Point) was simplicity and extrem low Weight - and though it was true (almost lower that the donor two-stroke) :insane: .... they did give up on that idea a few years later ....

I hope you will show some of your experiments here  :Love:     :cheers:

Per
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on September 22, 2022, 07:19:24 PM
Riding offroad is also great! Especially the mud seasons start right now. It is way more difficult and interesting to do than it looks on first hand! "oh I can also do that" first ride on sand or mud you changed your opinion. Ever been to Husquarvana museum? From Denmark it is not so far? Okay it is a trip you don't make everyday.

Thanks for the good vibe! Self I ride an old RD250C from 1976. Fast enough to ride on dikes and curved roads! And like to smell and simplicity and opportunity to improve/tune. Dad first bike was also an RD but than with round fuel tank, still have the original emblems of side covers laying in the garage.

Would update experiments here on the forum. First some theoretical calculations and 3d models  :cheers:
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on September 22, 2022, 09:29:12 PM
Let's start with primary engine balancing.

Some calculations and theory I found online and on a book of SAE. To think about loud, open maybe I miss something.


Theoretical (crankshaft part counterweight / part bigend and half crankweb) / practical weight of engine partsof current engine.

Piston and piston pen = 0,06342 kg
(Connecting rod = 0,04425 kg  - distance centre of mass underside connecting rod = 0,03053 m ;
Length rod (center to center) = 0,075mm    -> from bottom rod to center of mass = + rotating mass ; Top rod to center of mass = +oscillating mass)

Rotating connecting rod = mass rod * (Length rod - distance centre of mass underside connecting rod )/Length rod = 0,026 kg
Oscillating connecting rod = mass rod * distance centre of mass underside connecting rod  / Length rod = 0,018 kg       (rot- + osc mass rod =0,044 check)

Crankshaft throw (excl. counterweight webs) 0,183 kg

This result in:

Mass rotation = rotating connecting rod + Crankshaft throw = 0,026 kg + 0,183 kg = 0,209 kg
Mass oscillating =  Piston and piston pen + Oscillating connecting rod  = 0,0634 kg + 0,018 kg = 0,081 kg

So there we divided mass.

To calculate mass of counterweight of crankshaft = 1/2*mass rot* radius crank /radius balance (from center of mass counter weight to orgin/surface weight)

Using this formula you put in data only from rotating mass. Picture 1 shows a check 3d model whether it is correct. Here you can see that center of mass from rotational part of connecting rod + 1/2 of Crankshaft throw + dimensioned counterweight of crank give is almost at orgin of the crank axis. Picture 2 shows the center of mass from only the dimensioned counterweight (to measure distance orgin to center of mass for calculation (radius balance).

I recently understood that is possible to put a % of oscillating weight to the crank counterweight. Called 'normal balance'. For better balancing without using balance shafts you can use a percentage of 50 or 60% of oscillating weight. Only rotating mass -> counterweight -> first and second order mass forces to travel axis of piston. 100% added oscillating weight (and 100% rotating) would transform forces to perpendicular to piston movement. So 50% would divided the force and resulting in less noticeable vibration.

I think adding 100% oscillating mass to crank counterweight would be needed to fully balance 1st order mass balance. The counterweights of first order balance shafts would rotate other direction (clockwise) if crank spins counter clock (viewed from rear of engine). At the same speed as crankshaft.

Only thing is that when using 100%. That the second order forces would also 100% transfer perpendicular to piston movement (for the 55cc engine horizontal).
Maybe it is interesting to not use 100% compensate oscillating mass. But use a percentage between 80-100. So that not all 1st order get balanced but not all 2nd order shift to horizontal directing. To use no 2nd balance shaft(s), these need to have same mass as first order I could find, but spins at 2x speed of engine. If I am correct!

Formula of 'normal weight' counterweight crank = m normal balance = 1/2 * ((%m rot) *m rot + (%m osc) * m osc) * radius crank / r balance (from center of mass counter weight to orgin/surface weight)

Current counter weight mass = 0,5*0,209*(0,023/0,01553) = 0,155 kg = 155 gram (I see that I have a difference between calculation and actual build crank counterweight 146 gram)
For 100% osc mass "normal weight" -> = 215,2 gram (so need to add 64 ish gram per crank counterweight)

Easy balancing would be adding weight in 3x13mm holes. I was sure when building this 2nd crank that 100% rotated weight balanced ;p

[edit; I think I trust the center of mass calculation of 3d model of picture 1 more than calculating, difference is not to big)]

[Fig 6-44 of picture 4 shows balance shafts of first order, I think it is wrong showed. Because each first order mass rotate add counterwise rotation than crankmass(two shaft) to balance First force (2 balance shaft swing (two times half weight) to left, crank swing to right)]!


I think it is time call it for today and close my laptop!
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on September 22, 2022, 09:48:28 PM
Other thing. Started designing first order balance assembly to fit in crank.

I was thinking to fixing bush with bearing with sandwiching, two plates each side of bearing and lockup with locking assembly spur gear.

Already searching on the web for large shim or axial thust washers. 10-12 ID 30-40 OD?? Maybe someone now an supplier?

Greets.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on September 25, 2022, 08:04:59 PM
First order balance shafts

So time to calculate and design first order balance shafts.

Let's say we add 100% of oscillating mass to crank counter weights.

m rot = 0,209 kg ; m osc = 0,081 kg ; %m rot = 1 ; %m osc = 1

Mass counter weights crank = m normal balance = 1/2 * ((%m rot) *m rot + (%m osc) * m osc) * radius crank / r balance = 1/2 * (1*0,209+1*0,081)*(0,023/0,01596) = 209,4 gram

r balance changed now because we added weight to the crank, but not even and that changed or r balance distance.

Picture 1 shows designed counter weights to almost the calculated weight and r balance (y value 3D CAD). 208,2 gram.


Spinning this crank create a force horizontal of this engine view.

To design the first order mass of each balance shaft we have to calculate the counter weight of 1st order. It is like the same calculation of the crankweb but only there we to deal with only oscillating mass! And r balance (y value 3D CAD) have to come from CAD to put in the calculation.

mass 1st order counterweight = m 1st = 1/2 * m osc * (radius crank/r balance 1st) = 1/2 * 0,081 * (0,023/0,00983) = 0,0953 kg = 95,3 gram

To check this we calculate 1st order force and than the needed mass. for example n= 3000 rpm = w 314,2

First order force = F1 = m osc * r crank * w^2 = 0,081 * 0,023 * 314,2^2 = 185 N

Calculating the needed mass

F=m*a = m*r*w^2     =>   m=F/(r balance 1st*w^2)

Mass 1/2 for two shafts = 1/2* 185/(0,00983*314,2^2) = 0,0953 kg = 95,3 g



Picture 2 shows the designed 1st order counter weight that should be welded to a 10mm shaft.

Picture 3,4,5 display the designed balance shafts in the current crankcase.

The original back plate of the crankcase need to boring two 46mm holes. Using a boring bar it is for me difficult to turn this to a good tight dimension for a bearing.
So idea to turn bearing housings on tolerances. Add a o-ring to seal it. Shim the counterweight shafts and then lock it with a locking assembly.
It would be great if there are large OD shims available to also lock up the bearing axial. Or other I could use a tight fit or loctite on the bearing-housing.

The first order balance shaft should turn above current oil level. And have some clearance with the crankcase profiles.

Using 3x Black POM spur gears. d=54mm z=36 module 1.5. The width is 10mm but can be turned to thinner or thicker dimension because they came as 15mm thick. POM has a max surface pressure of 22 N/mm2. With 10mm width of gears you have a max teeth force of around 330 N -> 9 Nm of torque.
First I was thinking of using one brass and tow C45 gears. But POM is strong enough, less sound, I think no need of lubrication and lightweight.



In the crankcase there is room to fit a second order balance shaft. Weight of the counterweight is around 45 grams with a radius of 15 mm. Maybe one shaft (the one that have to turn same direction as crank) can be powered by the T5-10 valve timing belt. Need to designed.

For now. Only 2x 1st order shafts take 76,5% of total unbalance forces. And with one 2nd order shaft 88,3 %
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Admiral_dk on September 25, 2022, 10:20:00 PM
I might be a bit Thick here .... but why are you using two Balance-Shafts running the same speed as the Crank ...???....  I have never heard of any benefits from that approach ....  :noidea:

OK - just before pressing Post - I realized that the Crank + Balancer + Piston -> will result in a 'Rocking-Couple' and that can be elliminated with two Balancers ...!... but I have yet to see a production Engine with two running same speed  :thinking:


I forgot to respond to your RD250. I never saw one off these here in DK - but I had the 'Pre-Curser' to the RD350, as my first registrated MC was a R5-F from 1971.
Double Leading Drum-Brakes .... Freshly cleaned and one finger was enough to lock the Front + a week later you could pull the Leaver all the way into the handlebar and still pray for more braking power ...  :o
Clean & Repeat   :Doh:
It was also the last model with Piston-Controlled Induction ....  :(
I had some good times on that bike - but I sold it after eight months .... and even though I was a Die-Hard two-stroke fan until that bike - Way too Many problems => I have only own Four-Strokes since ....

For those that ride more sensible than I did - not neccesarily a problem .... and I hope that your RD serves you well  :LittleAngel:    :cheers:

Per
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: ShopShoe on September 26, 2022, 01:14:50 PM

"... but I have yet to see a production Engine with two running same speed."


Saab used two balance shafts for awhile in a 4-cylinder engine, an interesting concept:

http://www.saabwiki.info/index.php?title=NG_900/9-3_Balance_Shafts

--

--ShopShoe

Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on September 26, 2022, 02:30:53 PM
Older Saabs also used the Ford V4 as mentioned in the book extracts which had a single balance shaft.

As I understand the  twin shafts have to rotate in opposite directions so that the horizontal forces cancel out and the vertical forces balance the reciprocating piston.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on September 26, 2022, 06:20:24 PM
Good question.

Yes I think that Roger is right.

I think it is possible to use one primary balance shaft to counter the oscillating mass (piston ass. + half part is of connecting rod). I saw that on a 250cc motocross engine. I quest two shafts is more complex, space and costs. They may balance a % of oscillating mass and balance this also in % so there is still both vertical as horizontal 1st order forces. These forces result in a total lower forces that are less observable. I have read that vertically a engine and frame lever the forces better. And have taken the rocking movement for granted.



Years ago for a school project combined with a tractor pulling team / engine workshop we try to design a single cylinder test engine of one of them 8.8L big block chevy's. A challenge to design and build an 1.1L single super charged methanol feeded engine that should produce 250 ish hp at 10000+ rpm. Lot of heat and forces (also for the dyno of that hammering torque). Also for balancing the 1st and 2nd order forces there has to be large balance shafts that could handle that rpm. Maybe it was better to design a 2 cylinder boxer for that purpose (but than you have two variables). I would like to put that engine in a 500 hp 2CV! So far it was pure theoretical design.



So far I know they use for inline 4 cylinder (with 180 deg. crank not cross plane) two 2nd order balance shafts for the outward movement of the connecting rod and weight of pistons. One rotate the same direction as crank, other (same axial spacing) rotate opposite direction.

I was wondering about the balance shaft of that Ford/Saab V4. I saw that it is direct gear driven from the crank. Same dimension as crank gear and so rotate other direction than crank. Two weights on each side (180 deg. twisted). I don't know crank angle spacing of that engine (90 deg.?). It could be balancing primary forces or primary rocking motion (moment momentum)?



@admiral cool! I never have seen a R5 before. I see that these R5 engines produce more torque at even a lower rpm than a 1976 for example RD350. R5 36 hp 7000 rpm 38 Nm 6500 rpm and RD350C 39 hp 7500 rpm 33Nm 7000 rpm. They run on same carbs. I was thinking the go port membrane induction for what says on the side covers "torque induction". Port timing and port sizes etc might changed I see both have 5 ports.

The RD is still my first roadbike. Original it came from Germany, and so a German RD250C from 1976. Before year model C they had to modified the A and B models to reduce the power output to 27 hp. I read they have put larger exhaust headers than for example USA models. From 1976 they all produce 27 hp. In German you don't see a lot of 350, but mainly 250 because of this 27 hp, insurance technically cheaper (?)
Also the difference between German and not German 250C is that it have disc brake at front and rear. And a way larger rear light. These old days rear brakes are not the best. But with some modifications (steel lines, smaller master cylinders) the brake okay and more feedback. Tested the bike on the mountains this year, it is okay!
My dad have still a XT500 and learned riding on that bike. Yeah I do remember about riding with drums ;0 And liked the shaking of that engine! Whole front wheel moves when you stand at a traffic light.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Admiral_dk on September 26, 2022, 08:27:09 PM
I think you all oversaw the fact that I questioned two Balancers running @ Crank-speed/RPM ....  ;)

All the examples you gave are Balancers running @ Double Speed/RPM of the Crank .... (Second-Order).

I have a few Single Cylinder Engines (LS650 & DR350) in my possesion, with one Balancer and Yes - they are all (Spur-) Geared (with shock-couplings) directly to the Crank => Opposite rotation, with minimum extra Vibrations from the coupling medium. So an almost perfect First-Order Balance - just a small Rocking-Couple, as the point in the middle between the Crank and Balancer normally never is on the centerline of the Cylinder ....

R5F - Except that mine was Black & Silver-Grey-Metalic - this is the paint scheme :
http://www.pfeffer.ch/bilderr5.htm (http://www.pfeffer.ch/bilderr5.htm)
(http://www.pfeffer.ch/yamahar5.jpg)


Per
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on September 27, 2022, 06:06:18 PM
True! In theory one balance shaft direct under the centreline of crank/piston would do the job. And indeed you can ask your self what rocking couple should do on this scale model engine. But for double the balance mass there is my crankcase no place for a two times thicker balance weight or larger diameter. So would go with two!
Shock coupling is a great idea. I think, if spur gears are metal. They will also introduce a little bit of vibrations. Maybe POM gears would take care of that.

Great model to see. I was fun if Yamaha did build there twins with rotary inlet!
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on December 02, 2022, 07:19:00 PM
I would continue this balancing and oiling and other upgrades later. So I can fully focus on this project when I have the hobby time for it. I have already some nice ideas of using laser cut stainless steel sheet parts of making a secondary oil pan for dry-sump application. And use of hole / sweep cut out of sheets and press them together to make cooling channels for cylinder. Why not, just test it. Engine is already heavy!

Currently I am busy with building a mechanical geared clock as a gift for my grandfather! And need a quit a bit of programming and electrical designing.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on May 04, 2023, 11:06:14 PM
After a idea of a co-worker.

3D printed a Toroidal Propeller and fitted on the crankshaft. Just one from Grabcad.com, 200 mm diameter very thin layers.

Does it work? Check it out!

https://www.youtube.com/watch?v=vSVXlWPtbkc

Cheers

Found out that engine need larger jet.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Kim on May 04, 2023, 11:33:40 PM
That's pretty dramatic!

Seems like it might need to be a bit thicker maybe? :)

Kim
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Roger B on May 05, 2023, 08:22:37 AM
Oooops  :o

A bit of vibration as well  ::)
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Admiral_dk on May 05, 2023, 10:57:55 AM
Engine runs fine  :ThumbsUp:

.... but have a look at the video just before you destroy the Prop and see how much it flexes - no way it can be used for this engine ....
It needs to be much bigger for flywheel effect and structual having blades that are much much more substatial + made in wood, metal or solid plastic ...!!!
I can't see a 3D printed (of the kind we have @ home) make one that isn't dangerous ....

Per            :cheers:
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on May 05, 2023, 05:18:48 PM
Yes haha I also didn't expect the propeller to stay intact.
Maybe drawing on my own a Toroidal, but stiffer. And tune the printer on my own material (material here on work with these setting is better , now the layers did not melt together).
Or printing a turbine prop. But indeed it is still printed material and not machined.

Maybe wood would be better. I don't know how large propeller I can put on when engine runs max 3000 ish rpm and let say 1 hp.

Yes engine need some serious improvements of oil leakage and new cylinder and adding mass to crankweb (with balance shafts). But for now more things to do around home.

Alex
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on May 08, 2023, 04:59:34 PM
Well.. Just put a propeller on this engine.

After some search on the web. 18x8 should be on the smallest side of the 55cc engine. But engine has low compression. Only thing is that it is not a revving beast.

We will see. After building a proper test stand for this animal.
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: Admiral_dk on May 08, 2023, 08:35:05 PM
Quote
Only thing is that it is not a revving beast.

True and that goes for most of the Engine builds here on site ....

I immidiately noticed that you have a very restrictive exhaust system on the Engine in the video ....
But that is far from the only thing that has an influence on the revs and the power output.

Consider an IC Engine as an Air-Pump - how much can it Flow per Second and you have a decent idea about Power out. The highest amount of HP, I got from my Suzuki K50 in my youth was around 10-11 HP @ 10000 RPM and it only had a 'Static Compression Ration' (measured from where the Exhaust closes & up) around 4:1 - but it flowed perfectly .... So - No Kinks anywhere, or 'Jumps in Diameter' (can't be avoided between Cylinder and ports). Likewise sharp turns of the Gas are to be avoided too.

I used to put the system under the Watertap so I could see how well the Ports flowed - anything that didn't come out in a nice straight line, had encountered a problem.

Next - all the parts must be stiff (not bending) and accurately aligned - either parallel or perfect 90 degrees (Crank comes to mind in regard to the Cylinder) .... if not you either get too much Friction or maybe a broken engine sooner than later ....

Sorry for all my 'Ranting' - take what you can use from it and forget the rest  ;)     :cheers:

Per
Title: Re: Big stroke 55 cc one cylinder ICE
Post by: AlexS on May 12, 2023, 11:24:48 PM
No worry I do also rantling or rattling in my head about ideas. To much ideas.

Agree four or two stroke it goes for flow and pulling more fresh air and fuel in engine and out ! I have reed before some people did that back in the day testing with water, or it was you I reed before (Dejavu?). I could test engine without exhaust.

Tuesday I testrun it again just to play. I play with needle clip position and changing size 50 to 80. 50 is better and when needle at top position, leanest, engine won't run stationary. now middle position.
I do find out that when revving engine spurrs and way to rich (wet sparkplug, als oil but about that we don't talk about!).
Searching, for the 9mm carb size 50 is smallest, maybe it is 0.5mm. I have to make my own jets and theath it M6 outside, 0.3?
I can only tune the stationary screw.

I do found this in the attic of the garage. Kawasaki Samurai crankcases and 1 barel and 2 heads etc. I have met a other young guy at a two stroke meeting in NL that also ride and work on old motorcycles. He on a GT350, brother in law on a GT380 and his dad on a Samurai (I think) 350. Tomorrow I go to his place. Coincidentally I was planning get my dad's GT380 running. So tomorrow we could test the carbs "wet"the float heights, because today putting back the carbs after checking it has issues get left cylinder running stationary. I think incorrect fuel level. The main reason for working on the engine that one or more checkvalves of the CCI oil lines to crankcase is damage. It leak oil in crankcase over time. I might think someone try to compressed air through pipes that balls and springs got stuck. Found another one. Something I want to work on for years.

Admiral, if you are looking for a RD, I currently sell my because I want to work and ride the GT. Strange that there aren't many RD's there in DK. But before meetings I never saw one riding also here.. It is not a beauty queen, but did bring me fair to school work and Slovenia, UK, it is a good girl.

Okay back on the 55cc. I also found some old, 5!, front brake discs. I think of an old Honda. Because next to it there were large 2 cylinder gaskets (old Goldwing?). There is also a tank laying around and a lot of other stuff from a old boy next door (now an old neighbour) when he moved by boat to Aruba. Crazy. I remember come primary school here and bicycle in our street. Seeing an Nissan Pajero (80's) almost 45 degree hanging upwards on our driveway. The neighbour came back to an old Rolls (Silver Shadow) to pull the trailer. almost 20 years ago. Car stayed for couple of months on drive way, it was a mystery car. Shipped to Aruba.
Before he still lived at parents and in garden 20+ old V8 American and other large cars (remember when they ride by or got started). Most still waiting for working on or painting or whatever. Back at the yard next to a dry swimming pool and standing caravan there was grown a three through a rusted old car.
And of course a lot of old motorcycles GT750 Aprilia RS250 etc. Got to ride with him to get sand or look when he was working on the vehicles.
I missed that time.
Now they still comes in summer every couple or sometimes every year with his new family to us house.
I miss that time sometimes. I hope it remains possible for the future. To tinker with and drive old vehicles. Kids can play outside and try to build some nice things with just a hammer and wood somewhere in the village.
I rarely see it. Although recently 2 young girls were digging away a neat earth bump, which a net was laid down to pour a foundation. Have fun!

Great that now I met someone of same age that like the old stuff! It's not about possession. But for the stories and adventures. Something you see on the ride or have a good chat! Someone couldn't believe riding with two different size pistons is okay, he laughed. It is al about balancing mass! Even after 10+k km
But important new girlfriend also like it and is very brave to ride on back.

Oh wait go back, 55cc engine. Yes. I also found 5. Yes! 5 disc brakes. That was quit heavy and quit large diameter. Wait! Maybe it the next couple of decade. I could build a flywheel dyno with it. 3 were same size. So you can add on more discs to add weight.
Maybe think about to design test frame for, propeller, and flywheel dyno to calculate acc. time.

Well have a good night!
SimplePortal 2.3.5 © 2008-2012, SimplePortal