250r

[salinashbn831]

I recently got a piston kit for my Honda 82 250R i got a 72.00mm bore ... does anyone know what it goes up to like a 310 or wat .?

[Brittabrat]

Stock bore is 70mm so a 2mm overbore might make you around a 2-3cc gain in power, so you will have a 252-253cc machine, 254 if lucky. But that's only if it's a true 250cc, usually the real cc size is around 246-248 on a 250cc machine.

Piston size is a bad way to get power gain unless your getting a true "big bore" kit. Porting, raising compression and jetting are the best power gains for a stock motor.

Here is the normal equation: (bore2 x bore2 - bore1 x bore1) x stroke x 3.14 /4