Hi, my name is Steven, I'm a highly experience auto mechanic, Have owned several race cars and crewed on the Main and Martinets Top Alcohol cars that my dad has owned or co owned. NEW to two stroke. Being as I'm using my GI bill to finish school I don't have money for projects any more so I built my bike since they are good cheap fun. I have the 66 PK80 ebay motor kit on my Kent Del Rio and here are the mods NGK #6 range plug HD CDI kit Stuffed Crank case Arrow Reed Block PZ20 Keihin Carburetor Expansion chamber pipe (no name ebay but very Large high mount type) Transfer ports widened, de burred, aimed at intake, roof angle elevated to converge just below deck. Intake Widened, 3rd Transfer port added, port matched to reed block piston windowed, added transfer ramp bevels to top Exhaust port widened, port matched to ported exhaust flange. Raised Compression (not measured but nearly removed the sealing ring around stock head, its about .008" left) The mods have REALLY woke this little 66 up, it starts and idles fantastic, has amazing throttle response even with the large 20mm carb. Running the stock gearing (10/44) I get 41mph @ 9,212 RPM I was curious if this was respectable "race" performance or not. The best part is I got so lucky on balancing the thing is silk smooth with no vibration whatsoever. Im 185 lbs. My friend has a stock PK80 with raised compression, a banana chamber with muffler, and delorto 14 Carb, and short billet intake on his bike. I can leave his ass like hes standing still. He tops out at 29 after a LONG time. Mine gets up to 41 in (aproximation) 8 seconds or so? Wondering how to estimate HP on these things!