Gas scooter gearing

[lewis1914]

I am building a gas scooter. I plan to use a 79cc predator engine. The wheels will be 14" tall. I weigh 180 lbs. The scooter will weigh another 50-60 lbs. I don't need or want this to go very fast. The largest concern is that it climb semi-steep hills.


The lowest I can easily gear this without doing a jackshaft is about 6:1. Can I get away with using a clutch with this setup or should I use a TC? Would this climb hills?

The calculator says this (6:1) will go about 27 mph. This is actually much faster than I want. I would be quite happy with a speed around 13 - 15mph. This would be a gear ratio in the 10:1 to 12:1 range. I am nearly certain this would require a jackshaft setup. If I went this route, should I go with a clutch or TC?

 

[MWKarter]

Sounds kinda like a Tote Gote

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[Denny]

A centrifugal clutch would never last. You would need to use a TAV II CVT 30 series. The turd in the punch bowl is the 79cc Predator has too small of a shaft to use one. You would need to step up to a 212 for it to work. I know it is not what you wanted to hear. You can get a cheap 30 series TAV with a back plate for around $75.00 for the kit. Shop around. Do not use the belt in the kit or cheap belts. They will shread quickly! Get a Genuine Comet belt! They will cost a lot more but will outlast 10 of the cheap belts, saving you money in the long run.

 

[lewis1914]

A centrifugal clutch would never last. You would need to use a TAV II CVT 30 series. The turd in the punch bowl is the 79cc Predator has too small of a shaft to use one. You would need to step up to a 212 for it to work. I know it is not what you wanted to hear. You can get a cheap 30 series TAV with a back plate for around $75.00 for the kit. Shop around. Do not use the belt in the kit or cheap belts. They will shread quickly! Get a Genuine Comet belt! They will cost a lot more but will outlast 10 of the cheap belts, saving you money in the long run.

I can buy or make an adaptor to enlarge the drive shaft.

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I want to use the smaller engine in order to save weight and space -- the 20 buck difference in price isn't a consideration. The little engine is about 12 lbs lighter. The smaller engine will require more work -- the throttle setup is harder and the drive shaft size needs to be altered. Those are not issues that worry me too much.

 

[Denny]

The little engine is not going to have enough power for hills either.