4-stroke gas scooter build

[CI]

The only thing that could be making the noise is the clutch.
It is not a centrifugal clutch, but rather a stacked plate clutch, like on a motorcycle, but operates dry.
I think there is a little play in the clutch mechanism that may be causing the sound.
The clutch also has ball bearings in it, but those should not be operational when the clutch is engaged.

There is no chain or sprockets touching anything, and everything is carefully aligned.

I got the throttle cable repaired.
I had to make an end for it from brass, drill it for the cable, and then counterbore it about half way to make room for the solder.
Then I had to insert the cable, and flair the end slightly.
The drill bit for the cable hole was small and tedious to drill.
Rather an art to soldering the end onto a cable, but I got it done.

Tomorrow we go for a 4 mile run.
I think everything will work ok.
The jackshaft, rear axle, and associated bearings are built like a tank, so that should not be a problem, and those items operate freely without the chain attached.
The chain is a 420, so quite hefty.

We shall see.

Edit:
I probably need to verify that the clutch is completely engaging, and not slipping.
It does not seem to be slipping.

Edit02:
The idea behinding using a manual clutch instead of a centrifugal clutch is that the centrifugal clutch does not start to engage until the engine is at perhaps 2,000 rmp (according to one centrifugal clutch manufacturer).  So according to the centrifugal clutch manufacturer, if you try to operate the motor at lower than 2,000 rpm, the clutch will partially slip, and it will wear out quickly.
A manual clutch operates exactly like a typical motorcycle clutch.
When you release the clutch lever, the engine engages the drive train, regardless of the engine rpm, and there is no slipping.
So since I mainly have to go slowly at about 4 mph, I need the manual clutch, and the jackshaft/reduction ratio.

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[CI]

I added a sprocket guard, and welded on some cable support brackets.
Added a bit more air in the rear tire to give the pully slightly more ground clearance.

The clutch is what is making the noise.
When the clutch is pulled in, no noise, and when the clutch is out, the odd noise.
There are some ball bearings in the clutch, but they should not be spinning when the clutch is engaged.
I found some videos online where folks use these clutches on gocarts, for drifting, and they seem to be a robust clutch.
There were two spring options, heavy and light, and I went with the light spring option.

I went on a 2 mile ride, at full speed, which is about 12 mph.
A bit noisy, but everything is solid, and plenty of torque to pull up the hills with ease.
Plenty of torque at running speed, which is about 4 mph, so the gear ratio worked out well.
I checked all the bearings and the clutch for heat after the ride, and everything is cool to the touch, and nothing is out of alignment.

I think we are ready for painting.
It is a functional scooter at this point.
I probably need to weld on the brake bracket before I paint.

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[crueby]

Excellent! Going to make a trailer for hauling metal and casting supplies?

[CI]

I thought about making a pair of wheels that I could hinge down from the back, in case I every had to tow someone home.
My wife would probably not ride on the back of it though.
I carry her water, layers of clothing, hats, gloves, etc. that she peels off during the winter runs.
Sort of a support scooter.
My wife is a 5 time marathon runner, and countless 1/2 marathons and shorter races, so rather inspirational to me.
I can no longer run, but I can ride a scooter.

Edit:
With the jackshaft/gear ratio I am using (about 8:1 I think), I could plow with it easily.

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[vtsteam]

Wow, your wife is amazing!! 

Glad you got the scooter working the way you want. That was a fast project. 

[CI]

I am having trouble with several items on the scooter.
Hats off to anyone who has successfully built a functional and reliable motorized vehicle.

The sprocket on the left side of the jackshaft, and the pulley next to the rear wheel do not have enough ground clearance.
I added a guard on the sprocket, but the guard and the pulley drag on the ground if you turn too much.

I still don't like the speed range I have, and am still lugging the motor too much at my typical crusing speed of 4 mph.

I took the scooter apart the other day, and am relocating the jackshaft upwards to a location behind the motor.
I am increasing the size of the pulley opposite the motor pulley, and decreasing the size of the pulley at the rear wheel.
With an elevated jackshaft, this should resolve any lack of ground clearance issues.

I am having problems with the clutch, and for some reason it stopped releasing after a longer ride.
I don't have time to play around with the clutch, and so I am going to go with an all pulley and fanbelt design.
I adjusted the drive ratio to about 13:1, up from 8:1.
I purchased a few different size pulleys that I can swap out to fine tune the speed range.

I will use a pulley clutch, and I guess a footpedal, since I don't think a hand lever will give enough travel for a pulley clutch.
I found some examples of pulley clutches on ytube.
Here are a few examples of pulley clutches (idler clutches).

<a href="https://www.youtube.com/watch?v=Upw84zA1SRs" target="_blank">http://www.youtube.com/watch?v=Upw84zA1SRs</a>

<a href="https://www.youtube.com/watch?v=FUFq0NAPKGQ" target="_blank">http://www.youtube.com/watch?v=FUFq0NAPKGQ</a>

And I purchased a safety switch, which is used on boats, in case I become separated from the scooter, the motor will automatically turn off.
I guess if I have a clutch pedal, if I release the pedal, the scooter will stop (in theory, unless something jams the pedal).

My pulleys and belts have been ordered, but have not arrived due to the holiday shipping rush.
More photos soon.

Hopefully this revision will resolve all the lingering issues, and will be a simple design that does not have much that can break or malfunction.

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[CI]

One more pulley clutch video.

<a href="https://www.youtube.com/watch?v=clrI4-qzld4" target="_blank">http://www.youtube.com/watch?v=clrI4-qzld4</a>

[vtsteam]

I like the tractor version video.
re. the sawmills --- on mine I just slide the whole motor plate over. That's worked for 22 years.

[CI]

Nice sawmill !
My family was in the lumber business for over 100 years, until it got sold a few years ago, so I can smell that sawdust from here.

I considered just shifting the motor and plate, and have not really ruled that out.
No sense making it more comlicated than it has to be, and that is a really simple method (plate shifting).

My pulleys and belts may arrive tomorrow, so then it will be decision time.

Anyone have an idea about how to actuate the idler pulley using a typical motorcycle clutch lever mounted on the handlebars ?
I don't think the clutch lever has enough travel to move the idler pulley completely.

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[vtsteam]

CI, on mine there's a short section of square tube welded to the bottom of the engine plate. That slides over a longer piece of the next size smaller square tube that is fastened at both ends to the engine support frame. The edges of the engine plate just sit on the side support frames so it can slide along them.

My saw uses telescoping sections of 1/8" wall square tubing in a lot of different sections for guides. Most people say different sizes of square tubing won't telescope together because of the internal seam. But all I do is file that flush in a couple minutes hand work with coarse file. Then they fit great!

[CI]

 

[CI]

Scooter revision (?) is almost complete.
My pulleys and belts arrived today, and so I reworked the rear wheel shaft bearing supports, added the brake drum to the rear shaft, installed the belts and pulleys, and did a test run.
I still have to add the idler pulley clutch mechanism, but so far so good.
These belts and pulleys run very quietly, and the slower speed seems to be a better fit.
And no chains to keep oiled.

I purchased one size large and smaller for each pully, in case I need to fine tune the speed slightly.
I purchased belts a few sizes larger and smaller too.

Next up is the idler pulley clutch mechanism, and I don't have that designed yet, but will work on it tomorrow.
I probably need a guard on large pulley.

There seems to be plenty of ground clearnance with this configuration, so no danger dragging anything in a sharp turn.
I hope I am closing in on a good solution.
Everything looks pretty good so far with this setup.


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[CI]

I got the band brake set up and functioning.
Works from the handlebar lever via a cable.
One end of the band is cantilevered out from the frame on a round rod.
The brake cable attached to the other end of the band.
The band, when pulled, has to tighten in the direction that the drum is rotating, else the brake will not work.
Seems to work ok, but I have not tried it on the moving scooter yet.
I forgot to take a photo of it all connected.

While I had the rear axle disassembled the other day, I loosened the bolts that hold the hub to the two rim halves.
The hub does not lock in the rim concentrically, but I could see that the hole in the rim halves and the hub center were out of alignment, so I tapped the hub and got it a lot more concenntric with the rim.
I the latest video, there seems to be much less wheel movement up and down, so I think the concentric alignment is much improved.

I am trying to figure out the idler pulley clutch mechanism.
I considered making the motor plate slide, but what I really need is a clutch footpedal.
I may try to make the clutch cable-actuated, since I have some extra cable and sheath.
The largest cable I have is 0.108" dia, which is quite beefy compared to most typical motorcycle cables.
Cable actuation would allow me to avoid having linkage hanging down below the frame, and also avoid having linkage above the deck.

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[vtsteam]

 

[CI]

I started cutting out the idler pulley support pieces, but then my wife declared it "party time" and invited her family over.
Her brother cooked Cajun gumbo, and so I pigged-out all day, and did not get anything else done.

I am going to mount a cable support bracket on one of the engine bosses above the idler pulley, and pull the pulley arm upwards with a cable.
I will spring load the arm downwards.

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