alright this is my last question can u tell me ifa stock 400EX has 25 H.P and goes 65 mph.. Can u list sme mods that wilmake it go 70-75 mph and give it 40 H.P. thanks i swear this is the last question please tell me... and tell me how much all of it will cost ....

 

white bros rev kit, bore it and put a wiesco piston in, k&n filter charger, ct racing pipe kit, check a dirtwheels magazine for the prices

 

I heard bad things about the rev kits. It makes the bike hard to start in the cold and when the rev box kicks in the 400 is already done making power. I'd save the 100+ and put it towards a cam or something else. The xr400 cam is a drop in. And look at the HMF pipes I just bought one and installed it and am very happy with it. A cheap mod would also be to go up on the cs sprocket to a 16 tooth and mod the airbox. Good luck.