Valve clearances. How Critical??

The manual for my '78 KZ 650 calls for .15 mm valve clearance. How much tolerance will be acceptable? Most are at .12 or .13, however I have one at .08 and one at .20mm.
Thanks

.08 to .18mm for my GPZ750, loose is better then tight

.05 - 0.10 mm for the 750 twin. That's .002" - .004", I keep mine in the range of .003 - .005".

A shade loose won't hurt, but a shade tight will cause the valve and valve seat to burn up and your head is toasted.

TLH101 wrote:

The manual for my '78 KZ 650 calls for .15 mm valve clearance. How much tolerance will be acceptable? Most are at .12 or .13, however I have one at .08 and one at .20mm.
Thanks

I'm surprised the manual doesn't give a min/max range. The 0.08 - 0.18 mm number sounds reasonable, but the manual should say.

TLH101 wrote:

The manual for my '78 KZ 650 calls for .15 mm valve clearance. How much tolerance will be acceptable? Most are at .12 or .13, however I have one at .08 and one at .20mm.
Thanks

If the .08mm is on the exhaust side it's time to do the adjustment. That = .003" of cold clearance which is getting a little tight.

If not, those are temporarily, runnable clearances. What it can do though is cause uneven cylinder compression.

I suggest a tune up with carb synch is in the near future.

The clearances I have noted are "absolute" cold. Engine has not been started in quite a while.

If the valves are tight, they will only get tighter and once they are tight enough, the uneven cylinder compression will become no compression. Buy some shims in kit form from z1enterprises.com and pop the valve cover and get to it!

wiredgeorge wrote:

If the valves are tight, they will only get tighter and once they are tight enough, the uneven cylinder compression will become no compression. Buy some shims in kit form from z1enterprises.com and pop the valve cover and get to it!

And thank the Lord your engine uses the shims that are still available, not the 32 mm shims nobody sells anymore that go in my engine.

The .08 to.18 is from a factory shop manual. What size are the Z1/KZ900/1000 shims, I have a ton of them ?

Thanks for the feedback. The .08-.18 number was what I needed. I have a Clymer manual, & it only said .15. I knew there needed to be some leeway. I can swap a couple of shims and get all the clearances where they need to be.
Thanks