I am prepping my bike for the springtime by checking the shim clearances and measuring the size of each shim with a micrometer. I have the recording the following results:
right intake - 2.65mm shim - clearance is a hair less than .040mm
left intake - 2.65mm shim - clearance is between .05mm and .063mm
right exhaust - 2.7mm shim - clearance is just a little under .040mm
left exhaust - 2.75 shim - clearance is unknown as I do not have anything to measure clearance less than .038. Fortunately, the bucket does turn.
Given this information, what should I do? Should I replace 3 out of the 4 shims? What size should I use?
Isn't the range .03-.08? Sounds like you're good on all of them except the one. That's the same situation I'm in with pretty much all of mine. Less than my .038 feeler gauge, but the bucket still spins fine. I'll adjust them eventually but I want to get some riding in first. If you adjust any of the .04 shims I'd go for the right exhaust. You're gonna go straight from one end of the range to the other, but I think exhaust valves are better if there's a bigger gap than a smaller, for cooling reasons. Actually I would thing the tighter the gap the more air it would let out, so I might not be any help here. I would guess for the left exhaust you might want to go for a 2.65 shim, just a guess though.
I'd say you are good on all of them, I've even rode on zero clearance for a while :technical:
My new mechanic said he thought they were a bit tight. around .02 to .03 even though there were no real symptoms of tightness. So he took them to .08, synced the carbs, took away a bit of the leanness and she runs sweet :thumb:
Sounds like they're all within spec. Of course, if you want them to be the same as each others.....
Michael