Are new OEM shims completely flat, and are they surface hardened?

[Darkstar]

I just measured my shims and two appear to have slightly more wear in the middle than the outer edges. Is that by design or wear? Unfortunately, I only have a vernier caliper on hand, not a micrometer, but I'll be buying one soon. I'm asking this questions because I have very accurate lapping tools that I can grind shims down with, and finish the surface with 5000grit, without introducing heat. However, I'lll only do it if they're supposed to be flat...and they're not surface hardened, or someone here gives me really good reasons not to.

EDIT: I discovered that our shims are case-hardened, so grinding will not be wise. Mission aborted. Thanks anyway

[the_63]

I believe they have a chamfered edge, but they are flat as far as I know.

Chris

[The Buddha]

I just measured my shims and two appear to have slightly more wear in the middle than the outer edges. Is that by design or wear? Unfortunately, I only have a vernier caliper on hand, not a micrometer, but I'll be buying one soon. I'm asking this questions because I have very accurate lapping tools that I can grind shims down with, and finish the surface with 5000grit, without introducing heat. However, I'lll only do it if they're supposed to be flat...and they're not surface hardened, or someone here gives me really good reasons not to.

Oh yea they wear. I've seen them wear like a donut - apparently that is correct, the number supposed to be face down so that part is bathed in oil and doesn't wear as fast. They are supposed to be through hardened. Not just surface.
The shim IMHO should be flipped every check, but who does that. the factory installs them face down, and if they were in spec, no one would bother to flip.
The numbers - yea useless, I go by measure, but if they are worn in the donut shape, and your bike isn't wearing that valve the donut way, would you measure to the spot it wears in OK just a theoretical question, they should be within a squillionth of an inch.

Cool.
Buddha.

[Darkstar]

Uh oh, I've never seen you use the word "supposed" before. This will could either be a $70 order, or saving $70 and possibly having one break further down the road if they are surfaced. Guys on the vstrom forum say case-hardened and I'd be surprised a manuafacturer would change the process across models, I'm certainly no expert though. Maybe I should err on the side of caution and buy them.

[gsJack]

I never had any shim wear for 80k miles on my 97 and 100k miles on my 02.  Measured every shim I replaced at center and edges with a quality micrometer, all were perfectly flat and to marked size.     Only bought 6 shims for the 180k miles.

http://img.photobucket.com/albums/v443/jcp8832/GSvalvelogs_zpscvcef42y.jpg