So the truth is that my Puch Newport II has lost a step or two. The pipe mods I did are part of that, going from a 19mm PHBG to a 16mm also had a hand, and of course regearing the bike to deal with the Seattle hills knocks down the top speed a bit. In Columbus, the streets are pretty flat and allows you to get away with a much peakier set-up. Last year, I was really interested in the 'race to end all races' in K-zoo. Which is one reason I tried to step up development of the case-inducted ZA50, etc... Trying to compete with lots of 70 & 80cc kitted machines put my 50cc at a marked disadvantage. -And the nature of the race meant my 50cc motor would have to howl over 12,000rpm for many miles, obviously pretty risky. I had to gear tall. Really Tall. Unfortunately, there are physical limitations to sprocket configurations, which is why I schemed up this ZA50 primary drive gear. (obviously missing it's countershaft opposite) There are Up-gear kits available for lots of machines, but I've yet to see one for a puch. The idea was that I'd have a batch made, destroy the competition, then sell off the rest after the race. But that, alas, was not to be. I shopped around some local machine shops and tried a few online sources, but the start-up cost was more than I could afford at the time, and the production minimums dwarfed the realistic market. Anyways it didn't happen, and alls I gots is a blueprint and a dream, friends...
If you're curious, because this gear is for the 2nd speed only, it still allows for clutch stalling to get the bike into a rev-range where the 2nd speed can engage without killing the motor. Preferably on a long flat surface, such as Summit Av. or Kenny Rd. ... Because the primary drive & countershaft are in front of the reduction gear and sprockets, it has a exponential effect on the other gear trains.
Example: Puch ZA50 with a kit, capable of 11,000rpm
with standard 18:45 sprocket gearing =42.8mph
same set-up but with the T.Nspd. Upgear =60.23mph
or regear for more torque 18:64 and still go =42.8mph