I have a 400EX, and I plan on doing some more mods on it fairly soon. What would you all suggest? I would like to make it faster on the local MX track. Please help if you can. Thanks in advance for help.

 

install a cam, and a high comp. piston, if that isn't enough than get a Sparks 416 national kit...

 

I plan to add extended a-arms, and shocks. What kind of cam? What compression piston?

 

Sparks racing is very good they have been around for many years, i would probably go with their cam , a 10.5 to 1 cam so u wouldnt have to run race fuel...

 

what kind of shocks and a arms are u going to go with, im trying to decide for myself...

 

I think some Burgard or Houser Racing a-arms, and Works Triple Rate shocks.

 

Will that cam help me out very much? Will it still have plenty of low-end and acceleration as well as mid-range and top if I add the cam and the high-compression piston? Do you know about the price of the cam?

 

Would a Webcam and a JE 13:1 high-compression piston help out a lot with overall power on the track? Is the 13:1 too much compression? Should I just go with a Wiseco 11:1? Please help.

 

One thing is if you want to race AMA sanctioned 250 2 stroke you might want to wait before you purchase a piston. They may allow 440s to run where now they only let 416's in the 250 2 stroke.

I have Curtis working on my motor right now and hopefully the end result will be a 440 National. His 440 uses a sleeve that is the same thickness the entire length so you have to have your cases machined to allow for the sleeve. Also it allows you to use a larger bore size I believe you can go to 465 with his sleeve.

I have his X-4 exhaust right now it is really sweet. You can find info about sparks on his website.

Adam Smith
99 400EX

 

It all depends if you want to run race gas. 13:1 piston full race gas, 11:1 50/50 mix. I think personally that 13:1 would be perfect for the track.