'99 yz400f rebuild??

Hey guys, I've been riding this bike hard for many years.

The bike still starts easy and runs very strong, but I know it's past time for a top end and maybe more.

Is this something an amateur mechanic can handle?

What are things to look for once I have it apart?

Is there a big bore kit available for the 400 still?

any special tools I'll need?


If you follow the manual, and if you have good mechanical ability, you shouldn't have too much problems. I've rebuilt my 98 400 twice and can't wait to do it again.

Its not that difficult. Like the other post said, follow the manual. I also suggest using a digital camera if you have one and take pictures, at every major corner especially if you are not sure of what you are doing. You will in all probability not be able to complete the task in one day, so having the pictures will aid you in getting things back to where they are supposed to go. I also think it is vital that you get the various bolts back into the same holes from which they came, so marking them is important or place them in some cardboard mocking your engines configuration. To me the most difficult part of the rebuild was installing the cams and timing chain for the first time. It is a little tricky and will probably take you several times to get the timing marks aligned. Go slow and don't force anything! You don't want to snap anything here. Use a torque wrench and do the criss cross method during assembly as stated in the manual. If you don't have a torque wrench go out and buy one (sears) is good enough, you will use it more often than not....The best way to start this project is with a very clean bike. Clean it before during and after....

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