Yz400f VS Yz450f

Ive got a 1999 yz400f and i was wondering how i can get more balls oout of it. What is the difference between a 400 and the 450 can i just bolt the jug and head on from the 450 on my 400 and call it good or are they different??? Or where can i get a big bore kit for it besides max powers whole 1 kit they make for the 400.What is the cheapest easy way to give it more nuts???Please explain in detail!!! Thankyou

no , you cant put a 450 jug on a 400

however u can buy a 444 bore kit that uses a 97mm piston , and hotcams that would be a nice upgrade u can use a 12.5.1 piston ore a 13.5.1 piston

On his bike he would also need a 426 crank for the 444 kit due to the piston only fitting the larger wrist pin of the 426 rod. You can convert it to a 426 or a 444, check out lukesracing.com for more info. Or you can just mod the 400 with parts such as a high comp piston and hotcams and porting in the head. Do some searching and see what others have done.

thanks for the help

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now