On my 300ex I race a Warrior and a Z400 almost every weekend. Both rider suck and I always get the holeshot, but the Z is ALWAYS faster out of the turns but I can almost keep up with my aggressive riding. I need more mid-top power I don't need low I have no probelm getting the holeshot the kid on the z400 can't get the holeshot against a 250EX. I already have a FMF Powercore pipe and re-jet I don't know if my jetting is dead on yet please give me a approx size to use. Now I want to get more without getting too dangerous (blowing pistons, dropping valves) I ordered a 0.20 Wiseco 11:1 Piston and now I want a Cam, for mid-top. What is a good quality cam that performs well too. Do I have to install stiffer springs? another question what is a hardweld camshaft?

 

try messing with your gear ratio's that helped mine.

 

I am boring my out to a 380 here soon , that otta do it!

 

Anything over a 330 is a hand grenade. You'll go through trannys right and left. I've covered everthing you need to know about big bores on the X and EX in a previous post. It was titled something like advice for anyone doing a big bore kit on a EX/X.

 

I'm not really looking into a big-bore. Just a cam, port, carb. I am wondering what is a good carb and cam.