Originally Posted by Crisscrow
Yeah, I'm not looking to go 30 + sense that'd be against the law with no DL here, 20 would be fine, honestly I'd risk it if there were actually 33cc motors out there that look like the 49 and 66cc motors out there, but all the 33cc motors out there don't look a like.
One issue you mmight run into is that these engines can be quite underpowered when you go under 49cc's which means they may top out at around 20 to 25 mph like you want but you'll be pedaling a lot to go up any incline or may need to pedal assist it up to speed, but you Can go with a bigger engine and gear it down with a larger rear sprocket like the 50 or 56 tooth... The 50 tooth should get you around 25 mph with a 49cc China Girl type engine with decent acceleration and hill climb, same for the smaller 4 strokers too. But gearing it down will give you a lot more flexability to which engine you want to buy as well as keeping your budget low, the only real requirement would be that which ever kit you go with would need to be chain or belt driven and not friction driven.... A 49cc China Girl or 4 stroke engine geared to top out at 20 to 25mph would have all the climbing power you'd need once broken in, as well as excellent acceleration, even from a dead stop and a 66cc would accelerate or climb even better.