Ok, so i got his bike and it went 20mph.
I put a high compression head on, it has a 15/15 carb, a biturbo, 11th front sprocket and 45 or 46th rear sprocket. I also bored out the intake port to 14mm, exhaust to match biturbo, trimmed all gaskets, drilled out intake manifold. Polished exhaust port and roughened manifold/intake port. Why am I only going 25 mph? I believe the jet size is 58 or 59.
Any thoughts, other than that biturbo's suck?