40 mph is not that hard to do,I have stock engines doing 50 that I do very little to! Getting over 50 and having some good torque takes a bit of work then over 60 takes a bit more know how and a very good setup but ask any of his customers if they have gone over 60 and the answer is all way's NO,so paying $300-$500 for an engine that doesn't out perform a well setup stocker makes no sense to all of those whom have a clue.
Yup, if you pay $150 into a motor, then you still have $350 left to make it better, plus you'll find one in stock.
I can't say mine will go 40, I've never tried. 30 is fast enough for me, but I think it has some extra left in there.
You really don't have to do much,and to still be able to call it stock you can't do much! So when we say stock that means all stock components used in the engine,no port timing changes, no balanced crank's though truing it helps,no upgraded ignition,no so called high comp head and so on the only thing really needed to change is the pipe. The stock 44t gear is best suited to a stock engine as they need to rev for speed and the 36t just adds load that is hard to over come unless the engine is reworked,with stock port timing 11k (rpm) can be reached on the stock gear and 26" wheel just by cleaning the port's removing any flashing/casting flaws and widening them 1mm each side,getting the jetting/needle right with a solid setup no air leaks, chain line straight and smooth with as little resistance as possible.This video is getting old now but shows how a stock engine can perform with a solid setup and a pipe that lets the engine breath,this pipe is an old bertha pipe not tuned and has no boost/hit point in this video yet the bike can still just hit 50.
