Author Topic: Big stroke 55 cc one cylinder ICE  (Read 14990 times)

Offline AlexS

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Re: Big stroke 55 cc one cylinder ICE
« Reply #75 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.

« Last Edit: August 06, 2021, 09:14:27 PM by AlexS »

Offline Roger B

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Re: Big stroke 55 cc one cylinder ICE
« Reply #76 on: August 08, 2021, 08:04:46 AM »
That seems to be running well  :ThumbsUp:  :ThumbsUp:  :)

How is the test bed/dyno coming on?
Best regards

Roger

Offline AlexS

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Re: Big stroke 55 cc one cylinder ICE
« Reply #77 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! ;)

Offline Vixen

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Re: Big stroke 55 cc one cylinder ICE
« Reply #78 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
It is the journey that matters, not the destination

Oh! sod the journey, lets hit the bar and pool instead.

Offline AlexS

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Re: Big stroke 55 cc one cylinder ICE
« Reply #79 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.

Offline propforward

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Re: Big stroke 55 cc one cylinder ICE
« Reply #80 on: August 09, 2021, 05:53:58 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp:

That's a really well made engine - runs superbly!
Stuart

Forging ahead regardless.

Offline AlexS

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Re: Big stroke 55 cc one cylinder ICE
« Reply #81 on: August 13, 2021, 11:25:52 AM »
Thank you Propforward!
« Last Edit: August 18, 2021, 05:45:17 PM by AlexS »

Offline AlexS

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Re: Big stroke 55 cc one cylinder ICE
« Reply #82 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



Video shows run with stiffer valve springs, on camera it looks odd to see cam and tumbler motion ;p
« Last Edit: September 20, 2022, 11:22:48 PM by AlexS »

Offline AlexS

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Re: Big stroke 55 cc one cylinder ICE
« Reply #83 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.

Offline Admiral_dk

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Re: Big stroke 55 cc one cylinder ICE
« Reply #84 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
« Last Edit: September 21, 2022, 10:35:41 PM by Admiral_dk »

Offline AlexS

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Re: Big stroke 55 cc one cylinder ICE
« Reply #85 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.

Offline Admiral_dk

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Re: Big stroke 55 cc one cylinder ICE
« Reply #86 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

Offline AlexS

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Re: Big stroke 55 cc one cylinder ICE
« Reply #87 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:

Offline AlexS

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Re: Big stroke 55 cc one cylinder ICE
« Reply #88 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!
« Last Edit: September 25, 2022, 08:06:48 PM by AlexS »

Offline AlexS

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Re: Big stroke 55 cc one cylinder ICE
« Reply #89 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.