Fast

I haven't seen any records but some member of this forum have posted over 50mph on highly modified engines, I think Bairdco has been close to 60 mph with the reverse cylinder setup.

I've been in the low 50's numerous times w my 66cc bike w shift kit, pipe, etc.. GPS'd with a few different iPhone apps so maybe not scientifically accurate but repeatable enough to seem legit to me. I'd say my current setup id good for 52mph flat out.

Yeah I think my SBP front chain ring is a 44T and my old 7 speed freewheel is like a 12-34 cluster, and I've got the 10t final drive sprocket on the J shaft. The 11t was a little tall for 7th gear to get on top of. As it is, it's still hard to wind it out in 7th. I have plans to adapt an entire Puch stock cylinder to work on my bottom end, which will open up options for porting, pistons, intakes, and carbs that I'm used to from mopeds. I hope to tune the stock Puch jug to deliver the same or better performance than my 66cc China cylinder right now. I'm shooting for an honest 55mph as a goal. Shouldn't be too hard to get there with the stuff I'm contemplating. Probably rebuild the bottom end w new bearings in the process to make sure she's good for a lot of miles after the upgrades. This setup already had about 2000+ miles of hard riding chasing Seattle's Mosquito fleet and always cam back begging for more.