HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
BBrown626

Valve Inspection and Clearance Adjustment Limits

3 posts in this topic

Hi guys.

I am in the process of adjusting my valve clearances by replacing a couple shims. I previously had a shop do it (last year). The tech told me that one of the exhaust clearances was tight and he fixed it. I recognize that shim because it is a 180 rather than a number I can't get at the shop. All the rest are the original shims and therefore my baseline.

So knowing most of my baseline, how do I know when I should stop shimming and address the wearing of the seating surfaces?

The bike is an '04 YZ450F.

Brent

Share this post


Link to post
Share on other sites

Since the hard nitride coating on the valve face is so thin (<.001"), almost any wear at the valve face means trouble. If you ever find a valve that needs a shim 0.10 mm smaller than the original, you most likely need a valve job. The giveaway will be when you ride the bike one more time and find that it needs to be reshimmed again afterward.

Share this post


Link to post
Share on other sites

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
Sign in to follow this  
Followers 0