[RacinNinja]

Originally Posted by kxpower?

I don't know a whole lot about the hardening process, but here's how I have seen it done for the 29.5 mm shims both my Suzuki's use. The shims are stamped at the factory with the thickness, which, if that side is installed down that side is basically stationary other than spinning in the bucket. Which is a lot of movement but not nearly the action the top side is getting from the cam.

When you grind a shim (my brother did a few with a mill a while back) just grind the side where the thickness was marked, so you don't have the wrong thickness. Then install that ground side down. That way if it's lost any hardening from the grinding, it will be on the side that doesn't get beaten on thousands of times a minute.

Oh, and I don't know if it's an issue for the Kawi's, but I remember receiving an adamant warning to make sure the shims are NEVER exposed to magnetism. Apparently a magnetized shim could stick to the cam and lift out of the bucket in a perfect storm and wreak a lot of havoc in your motor. Fishing those suckers out of the head I could see the temptation to grab it with a magnetic screwdriver. I used these huge 6-inch long tweezers and they worked without a whole lot of cursing.

This doesn't really apply to Ninja's and most (!) motorcycles as they are shim-under-bucket (yes, I know a few are shim over bucket). IE, the bucket is what makes contact with the cam, and the shim is a tiny little thing riding on top of the valve stem.