Fozzie

Hi, i'm looking at buying a nice little 4-stroke for my first bike just to act as a commuter and to get my experience up. The problem is that if I were to get a 125cc 4-stroke it would be barely kicking out more power than my old Aprilia RS50, which was tuned to the point it did 80mph. The bike i'm looking at has a Yamaha TTR engine. Does anyone know how to tune these engines so that its giving hp thats in the mid- 20's. Ive got plenty of money to spend and I DONT WANT A BIGGER BIKE. Is there anyway to change the timing of the valves? Sorry i'm a noob with 4-strokes because i've lived with 2-strokes all my life.

It could be the powervalve or it could be something much worse and far more expensive. If the engine is a 2 stroke then the crank case seals may have worn out and aren't keeping enough pressure to take you above 7,000 RPM as the little machines need the crank case seals to help produce pressure and force fuel into the engine. What revs does the bike go to before it splutters. After you've sorted the powervalve out, if you still have the same problem it will be the crank case as my little 2 stroke did the same.