Mine is still a work in progress, with the SBP pipe and 40 tooth rear I am topping out around 25-26 mph according to a "speedometer" app on my iPhone. No tucking and I weigh 230. I ordered a 5.5 compression Fred Head and a new piston with a good size hole / window in it for the reed valve. I have run 1 tank of fuel thru it. Looks like I will have to throw more money at this engine as so far I am not very impressed. I have another bike with a BEKITS (Cheez) motor, billet head, speed carb, 40 tooth rear and basic expansion pipe and it is about 3 mph slower than the GasBike GT-80 which has all the "speed parts and porting"
Also vatoed, I have a DAX motor and it is a nice motor but no where near a "Hot Rod" engine. It has the Puch head from DAX, speed carb and basic expansion exhaust.