I checked my valves last night, and both my exhaust valves were .01 tight. I've heard of people shimming their valves up when they were "towards the tight end of the range." But Yamaha only makes shims in .05 incriments, which is also the acceptable tolerance range (.20-.25 for exhaust valves.) So, if you weren't clear out of this range and put in the next bigger shim, you would be out of the range on the loose end. Are there shims available in smaller incriments? And just out of curiosity, how tight would valves have to be before doing damage?