Best 4 Cycle Combo?

[Deleted Member 4613]

Was this problem ever solved? The best idea is go with Grubee tapered shaft engine
and 4g belt drives. The Grubee clutch/trans uses sealed ball bearings - no oil lite
bronze bushings. I have the q-matic, and it's solid. I'm going to guess that the
engine shaft is not rotating at the center for some reason, and is creating
stress on the bearing. Is this stupid or not? But the whole kit is made in China, so
anything is possible. Thinking more about this, I'd say if the bushing is over-heating,
it's a symptom of friction caused by excessive binding, meaning that something
is out of alignment, either the bushing is out-of-round, or the shaft is not
rotating at the center. No amount of lubricant can resolve this.

 

[Will'smotobikes19]

I agree tapered shaft with a better gearbox. I wish there was a gearbox that would work with straight shaft to replace these ebay transmissions. 79cc can give slightly more torque but the rpm is less and the gearbox has similar problems as the straight shaft 49cc plus it's heavier with the same basic top speed (you'd be surprised the truth is the huasheng has a higher redline being atleast 6,800 rpm or more depending vs 3,600. Centrifugal clutches mostly use a bushing which wears out and the whole thing wobbles and makes noise. The bushing is absolute crap and a design flaw.

 

[Will'smotobikes19]

Does anyone know the wall thickness of ebay bushings for the 49cc? There might be a needle bearing that's thin enough. Something like 2mm or 1/8?

 

[Will'smotobikes19]

https://www.ebay.com/itm/144018037422?epid=28019584778&hash=item218824daae:g:3mMAAOSwf4hggyah
What I'm thinking is you could drill a tiny hole in the washer at the end of the shaft to oil it and press the needle bearing into the clutch bell??

 

[Deleted Member 4613]

The trans and clutch should not be wobbling. I believe you have to inspect the
bushing and shaft and clutch with a caliper and micrometer, to determine which and where
the parts are distorted or out of alignment. I suspect when you first rode with the
bushing binding, you unfortunately damaged the bushing. Oil will not fix this.
You first have to locate the problem. Don't ride the bike with a wobbly trans.
Measure the bushing carefully and order a new one if you determine it is damaged.
I know BGF has these bushings and there may be other sources once you know
the dimensions. There has to be a cause and if you inspect the parts carefully, and I
believe you will find it. My opinion.

 

[Deleted Member 4613]

I may see a couple of problems here, maybe three:
(1) It looks like the original bushing is bronze not Oilite,
which means it can only work with grease.
(2) I discovered that the factory way overtightens the
belt which is very hard on the bushing should it lose
grease. Re-adjust it.
(3) Never ever sand or put grease on an Olite bushing. Sanding
it lodges grit in the pores, and grease also reduces free flow
or release of oil to the surface under loads. Use only
oil, 30wt SAE.

 

[Sidewinder Jerry]

CC for CC, I think I've done pretty good, triple chainring shift kit 3×7 drive system. Reduction range 66.79:1 to 16.25:1, may even be the widest reduction range ever on both forms. The wide range allows the 33cc 4 stroke engine to be a real work horse even though I'm a large person and live in the mountains.