Ok due to age this is the first year for 4 stroke. I have the chassis down, same needs and set ups. i'm looking for some mods in the motor. We went with the 400 for the school boy senior class so it has to stay 400 or less. It came with a FMF slip on and that is it. This thing is in amazing shape, you could have put it on the show room floor. Ok enough of that because after a few motos that will change, I'm looking for some economical internal work that would liven it up alittle more, any ideas would be great and appreciated.
Thanks in advance.

 

Port the head, Hi comp piston, cam.

 

HMF full system instead of the FMF slip on.