2-speed Puch clutch modification

Gregory Mcintire /

Maybe someone else will find this useful. It sure worked nicely for me.

I recently discovered a way to modify the tranny of the 2-speed Puch to increase the RPM of the second gear engagement, and also to decrease the difference between the 2nd gear engagement and disengagement RPM.

My 2 speed used to shift into 2nd gear at 17 MPH and shift back into 1st gear when the vehicle speed was reduced to 13 MPH. This can be a nuisance when going up a very steep hill. By the time it shifts down into first gear you have lost too much speed.

By studying the construction and design of the two clutches it appeared that flipping the 2nd gear clutch around (front side to back) might reduce that difference between the upshift and down shift speeds, which is what I wanted. I tried it and it works great. In fact, It now shifts from 1st to 2nd at about 20 MPH (engine is at 6000 RPM) and shifts back down to 1st at 19 MPH (engine is at 3800 RPM). This is using an 18t front and a 35t rear sprocket.

Re: 2-speed Puch clutch modification


That's really interesting. What about the clutch design made you think that? I seem to have unitentionally modified my 2-speed, I'm not sure if it's for the best though.




Re: 2-speed Puch clutch modification

Gregory Mcintire /

The fact that the little linkages which the clutch shoes are attached to (they look like chain links) are laying at an angle. This would cause the second gear clutch to grab harder once it initially makes contact with the drum. You must consider that the drum is spinning at crankshaft speed which is faster than the freewheeling second gear clutch shoes prior to shifting into 2nd.

The two clutch assemblies are supposed to be installed such that the three little "chain link" components are angle and pointing oppositly from 1st gear clutch to 2nd gear clutch. But now I have the 2nd gear clutch angled the same way that the 1st gear clutch is.

Due to rainy weather I have only driven the moped about 120 miles since doing this but it has not had any adverse side affects so far.

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