The left intake shim on my bike is stamped 250 and measured 250 fairly accurately with a micrometer.
However I needed to change it as it gave me a .09mm valve clearance.
Haynes lists the correct valve clearance spec should be between .03mm and .08mm.
A .1mm feeler gauge leaf would not fit. The .09mm feeler gauge leaf did.
So I bought a 255 shim to get the valve clearance down to .04mm.
I've just replaced the 250 shim with a 255 shim and I cannot fit .03mm feeler gauge leaf.
It's probably close and one of the tools is probably off, I'm guessing the feeler gauge set as my micrometer is decent.
What would you do?
Use the 250 shim so you are a little over spec or use the 255 shim so you are possibly under spec?
leave it at 0.09mm.
Over spec (too open) better than under spec (too tight). I'd go open and not worry at all.
Quote from: mr72 on July 09, 2018, 09:41:38 AM
leave it at 0.09mm.
Quote from: Rallyfan on July 09, 2018, 09:55:27 AM
Over spec (too open) better than under spec (too tight). I'd go open and not worry at all.
Thanks guys for your prompt replies. As you both suggest the same advice, I will take it and I guess I'll put back in the 250 and I have one more shim to change.
I did the other three and they are now in spec. I find this job very stressful. The shims are so tricky to get out and in although I think I've mastered taking them out now.
Getting in the exhaust ones especially to seat, they always tend to slip down past the cam bucket and miss it. Then you have to get the gasket to seat in the valve cover and pray it doesn't come off when you go to put the cover back on >:(