long case, short case, gearing swappable?

[benhonda]

I just got a parts bike that has 12'' wheels and a long (or at least medium) case.

I have a 50cc turned into an ATV trike that has 10" wheels and a short case.

Am I correct in thinking that the different length cases have different gear reductions to account for the different size tires?

If so, can the gear sets be swapped?  If I put the gear set meant for a 12'' tire into the rig with the 10" tire then it should be quicker off the line, have more torque down low.

Maybe a pipe dream, just thought Id ask.

[jeff84]

definitely maybe

[Zino]

Yamaha minnarelli short case vino gears are nothing like Yamaha zuma long case gears .

You will know when you crack the tranmission case if they swap.

I went from 14 to 1 to 11 to ratio on my zuma
The take off and acceleration were very similar .

The way the cvt works when properly balanced, I had the engine spinning up before take off to where it makes the most power .

Now if went below a 10 to 1 ,I may not be able to over come it with stiffer clutch springs and lighter variator weights.

Here is a thread of various scoots gear ratios

49ccscoot.proboards.com/thread/1265

[Zino]

For take off
I would focus on the variator and clutch ratios .
For take off you need the belt maxing out the pulleys .

here is a video on shimming it also shows how far you can max out ratios
www.youtube.com/watch?v=z6bwq2Mq6p8&t=3s

[GrumpyUnk]

You will know for sure if you remove the CVT cover, mark the wheel(or gear) and the clutch cover.
Rotate the clutch cover, counting revolutions, watching the output shaft spline or the wheel.
I suspect that most will use the same ratio for 10" and 12" wheel sizes. I have one with 13" wheels in the garage, but I have not counted to see...
I was going to replace the gears in the gearcase, actually bought new, but just replaced all the ball bearings & seals. The gears I bought were exactly the same as what was in the original. Except for the fact their supplier sold them gears that were oversize in diameter, the gears were exact duplicates. I had to provide pictures of the old and new, along with a micrometer showing the problem measure and even emailed back to the China support crew. They found the gears sold were incorrect. Guess no one else bought them??
Anyway, I would bet the ratio is the same. It seems most of the 'performance' gears are the last pair in the geartrain, and several ratios are available(at least on aliexpress). The gears in the 150cc(and larger) machines are similar in design, but I expect them to be larger to handle the higher torque and power.
tom

[benhonda]

Jan 30, 2020 9:23:17 GMT -5 Zino said:

For take off
I would focus on the variator and clutch ratios .
For take off you need the belt maxing out the pulleys .

here is a video on shimming it also shows how far you can max out ratios
www.youtube.com/watch?v=z6bwq2Mq6p8&t=3s

I have worked on those parts

I was kind of wondering if the gear sets could be swapped, because it would be sweet if I could put a bigger tire on it