Update On Oilite Bushing/Bearings Conversions of 4 Stroke Belt Drive

Nirve

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Unfortunately Mike, I must have not explained this "gap" well enough in the first paragraph of post #22. It was the best I could do.

My clutch installation yesterday works perfectly. I was able to stop the large pulley from kissing the bell by first removing the black steel ring on the rear. Just grab it with vise grips and twist it back and forth, it's a press fit. The teeth are actually machined into the aluminum casting and are not a separately applied component as I had previously thought. There was still minimal kissing going on which I eliminated by placing some emery cloth at that point an spinning the large pulley until it was no longer there. .It still wobbles but the belt tracks well. It tends to track on the small pulley against the bell which keeps that 1/16" endplay on the spacer washer open. Finally I have this running to my satisfaction. It would have been nice had they furnished a second end cap to go in the bore of the large pulley. If I machine a longer one someday for the clutch I will use that one. The belt dragged on the lower portion of the cover with a half inch gap on the top. Unbelievable ! You'd think they could make this fit. After elongating two screw holes and drilling a new one for the bolt the cover fits properly. It'll be a while before my bike is on the road so keep us all informed on how yours is doing.

I'm anxious to see how much extra effort is required to pedal the bike with the engine off seeing as this trany does not have a freewheel. Maybe a tapered shaft engine's 11T drive sprocket with a freewheel will fit our shaft. Something to research for sure.
Hey Michael, I’m positive that this setup will fit and could replace your pulley. https://www.bicycle-engines.com/4g-...rocket-for-grubee-4-stroke-t-belt-drive-kits/
I just put a Grubee 80t pulley on my Amazon belt drive and that fit, so the freewheel one should fit as well. It would help with the drag, it would also make you able to coast with the engine idling
 

Mike St

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Nirve, are you saying the 80T large sprocket on bicycle-engines will fit
on the chinese belt drive? This is important since it would lower the
tranny gear ratio to 4:1. Is this what you are saying? I don't know what
you are saying about the freewheel. I suspect you are saying you
think the Grubee clutchbell will work on the 15mm shaft engine
which is won't. Please explain.
 

DieselTech

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Nirve, are you saying the 80T large sprocket on bicycle-engines will fit
on the chinese belt drive? This is important since it would lower the
tranny gear ratio to 4:1. Is this what you are saying? I don't know what
you are saying about the freewheel. I suspect you are saying you
think the Grubee clutchbell will work on the 15mm shaft engine
which is won't. Please explain.
No I believe he is saying they make the driven pulleys in a solid version or 1 with a freewheel installed in pulley.
 

Nirve

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Nirve, are you saying the 80T large sprocket on bicycle-engines will fit
on the chinese belt drive? This is important since it would lower the
tranny gear ratio to 4:1. Is this what you are saying? I don't know what
you are saying about the freewheel. I suspect you are saying you
think the Grubee clutchbell will work on the 15mm shaft engine
which is won't. Please explain.
Hey Mike, yes, I can confirm, the 80t large sprocket from bicycle engines fits the Chinese belt drive. To confirm, measure the shaft, it should be 15mm. I did it to obtain a 4:1 ratio on my BMX. Check out my post, in the pictures you can see both the 100t and the 80t belt sprocket.

About the freewheel: If you prefer having a freewheel in the large sprocket, you can: https://www.bicycle-engines.com/4g-...rocket-for-grubee-4-stroke-t-belt-drive-kits/
If both pulleys, with or without the freewheel are made for the Grubee trans, and one proven fits our Chinese trans, therefore both fit our Chinese trans.

About the clutch bell: I didn't mention anything about the Grubee clutch bell. You can use the Chinese clutch bell. If you buy a 80t pulley, you will have to buy a smaller belt though,

hope this helps!
 

Mike St

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OK, I understand what you are saying. This is great to know I can
change out to the 80T and of course buy the 80T belt. I'll
definitely take a look at the 80T with a freewheel. Sounds like
a terrific idea. Thanks. The world turns in strange ways.
 

Nirve

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OK, I understand what you are saying. This is great to know I can
change out to the 80T and of course buy the 80T belt. I'll
definitely take a look at the 80T with a freewheel. Sounds like
a terrific idea. Thanks. The world turns in strange ways.
Good luck with the project! If Don gives you s**t, this belt might work from amazon. It says it has the correct dimensions: https://www.amazon.com/PowerDrive-505-5M-15-Timing-Belt-Rubber/dp/B00ISC6FNS

Tips for the install:
  • You will need the spanner wrench to adjust the eccentric cam
  • If the pulley (sprocket) doesn't slide on easily, do not hammer it on. Take a socket head screw and screw it into the shaft, attach a drill to it, spin the shaft and sand it down a thou. I tested the pulley on two different Chinese belt transmissions, one fit just fine, one needed sanding for 2 minutes.
  • When adjusting the eccentric cam, you will change your drive chain tension.
  • The pulley has two sides, one is closer to the engine, one stands off a little bit more. I was able to use the closer one for perfect belt alignment.
Let us know how it goes!
 

Nirve

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That's what a forum is for!
One more sweet update for the Chinese belt transmissions: get these springs from bicycle engines when you order anyway. They're stronger and make the clutch engage around 3000RPM instead of 2000RPM (tested with a tachometer). That helps with clutch stutter and power to get going, as well you can raise your idle RPM which makes the engine easier to start!
 

Mike St

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Another great idea. I've asked before if anyone knows about these
clutches and got nothing. YES, my trans engages too quickly, at
idle, it pulls slightly which I don't like. I will order these springs
and install them. I have some work to do after I finish with my
new 24 inch rear mount, which uses a Subaru 35cc engine,
and a scooter 5:1 gearbox, doubled right sided drive. Thanks
again. I appreciate it. Mike
 
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