That's not true. If it's like any other 4-stroke, it can make a big difference. You can alter where the motor produces it's power and how much by altering the timing. You may have to add stiffer valve springs. Not sure. The drawback is it may be harder to start and more tempermental. Depending on which cam you choose it can cost you some low end.

OH, how I love that hot cam idle!

 

When I had my 400EX, I put in a JE 10.8-1 416 piston kit ($140), a Hotcam Stage II cam ($125). The boring and honing were around $80 if I remember correctly. I also changed out the valve seals and retainers, around $30-$40.

 

ok, thanx, so for my first bore will i need a new sleeve? or can i just bore out the origional

 

you use the stock sleeve. the stock one will accept up to a 426.

 

I didn't like the stage 2 hotcam, spend the extra money and get a Web cam with hardened rockers and stiffer springs

 

420ex, what kind and where were the power gains with the webcam

 

what does it mean to hone a cylinder

 

i had good success and power gains with the hotcam. different cams will produce power at different rpms. everybody prefers something different. you can call C&D racing on cams. the # is 308-696-7805.

honing the cylinder is like scratching it up a bit. when installing a new piston or new rings, the cylinder needs to be a little rough for the rings to seat properly. this will provide a good seal and produce a better running bike.

 

If you run trails, all you need is HC stage 1, a good slip on (not a header), a good filter with no lid, and proper jetting. Excellent low end!