would i be able to put together a 440 kit ina 400ex by myself? my dad works with cars everyday and knows how to rebuild engines realy good and that sort of stuff. he has all the tools he could bring home and help me but i was wondern if theres a kit you buy and put it on yourself. ive only herd of people sending engines into the manufacture to have them do it. also what other things would i need and whats the best kit for the money?

thanks

 

you will not be able to press the old sleeve out of the cylinder, bore the cylinder for the larger sleeve to fit, press the new sleeve into the cylinder or bore the new sleeve to match the 440 piston. you will be able to install everything though with a service manual for the 400ex. you will want to make sure there is slack between the cases and the big bore sleeve. if it is a snug fit, when the engine heats up the metal will expand and this can put pressure on the piston. i recommend a je or ross piston. i ran a LA performance sleeve.

 

If your bike is stock you'll see minimal hp gain. If you have'nt already done so you'll want to get a higher lift cam, bigger carb, exhaust, filter,cdi box, and maybe an IMS gas tank. I'm not sure about a stronger clutch.

You'll get the full potential of a big bore kit. W/ all of that, roughly, you'll be getting maybe 45 horses!

 

your quad will be alot better.

 

If you do decide to get all of that stuff, I'd just buy a kit form a company (such as CT) because they tune THIER cyilinder's,THEIR cam's, THEIR piston's to work the best together. And what carb size works best