Today is my birthday and tomorrow is "Race Friday" here in my town and well thank goodness for good friends. My buddy gave me a new Ross 12:1 High Compression piston and gasket kit for my 400ex and I thought maybe about tackling the task of putting it in tonight and working on it tomorrow before the race.

My question is this: Do you have to Bore your cylinder to have a high compression piston???????

It's standard bore by the way.......[img]i/expressions/face-icon-small-confused.gif[/img]

 

The Compression ratio and the Bore are two diffrent things, they will both boost your power. A higher commpression Piston means that there is less room for air when the piston is at its highest so the fuel is burned more efficently and that is why you gain power. The Bore is just how big around the cylinder and piston are so when its bored you suck in more air and fuel on the intake stroke, also gaining you power. Of course for the most power you buy a high connpretion pistion that is over sized and have the cylinder bored to match, then you get the combination.