where would be the best place to buy and 80mm piston. Would a stock carb off a 400EX add any extra power? if so what would you start the jetting at? (right now it just has a high compression piston and cam.

 

In order to run a 80mm piston you need to resleve the cylinder. FST sells a kit for this. www.fourstroketech.com As far as I know the 400EX carb is 3mm bigger then the stock 300EX carb and you should get more torque out of it. It might be cheaper to just bore out your stock carb then dropping down money for a 400 carb. If you want to get a 400EX carb check out www.servicehonda.com.

 

Thanks for the reply, I already have a cylinder with a 80mm sleeve in it. I was looking on E bay for 400 carbs. I can get one for less that 100 bucks.