Lash me whip me, you know I need it

99 WR400, new head & valves. This is the first valve lash adj on the new head. I have R&R the shims & 4 of the 5 valves are within tolerance now(previously all were 2-3 hundreths of a MM tight. Now 1 of the intake valves is 2/100ths of a MM loose.

Yamaha intake specs= .15-.20MM

old lash=.127MM with the 191 shim

new lash=.22MM with the 185 shim

Old shim was a 191, new shim is a 185. Yamaha only sells increments by 5, i.e. 185, 190, 195 etc. I was previously using the 191 & it was slightly tight whereas now it is slightly loose. I could go to a 190 but how much difference there would be from the 191? I could also hand lap the 191 down w/ 600 grit but I only need 2/100ths of a MM. Any ideas about running the current 2/100ths of a MM loose or should I order the 190 shim or lap the 191?

Thanks for your support :thumbsup:

Don't be obsessive about vlave lash. I didn't even know you could get shims in less than .005mm increments

In the past you were able to obtain shim's in increments by one, now Yamaha only sells increments by five.

If you can't dial the clearance in to spec then err on the loose side. You should be fine :thumbsup:

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