hi, I just bought a 2002 yz426 and wanted to know how reliable these bikes are and what is the fist thing to wear out, how often do you have to rebuild the top end and what are the best mods.

They are in the same league with claw hammers, anvils, manhole covers and sundials as far as reliability is concerned. However, it's an 8 year-old bike. There's no hard rule for how often you rebuild them; it's much more an "as needed" kind of thing. The rings and cylinder should ordinarily need attention before the valves do in a YZF. Doing a valve job using titanium valves can be a very expensive proposition, but the thing about any 426 is that you can substitute the stainless valves and valve springs from a 2000 model for a quarter of the price.

A leak down test will tell you a lot about the current condition of things, and you should also check to see where your valve clearances currently are.

Regardless of its condition, do yourself a favor and replace the cam chain as a maintenance item.

+1 on gray's advice.:p He know what he's talking about.

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