1985 K100RS valve clearance check advice needed.

I checked my valve clearances today. Intakes were all .15 go and .20 no-go. The exhausts were all .25 go and .30 no-go. My issue was that #4 exhaust was a .25 go with effort but it did go. I do know that the 2-valves tend to tighten over time and I'd rather not run the risk of burning an exhaust valve. Will I be okay? Bike has 30K miles and I can't tell you when they were last checked and what those clearances would have been. I am going to go back in and get out some different gauges and try to determine what it actually is by comparing the relative resistance felt with the .25 gauge on valves 1-3.

Thanks,
Tom

Tom,

I prefer to use inch feeler gauges vs metric. Set the intakes to .006-.008" and the exhausts to .010-.012" with .012" being highly preffered.

The advantage of using inch feeler gauges, besides being cheaper and easier to find at any car parts store or Harbor Freight, is you have the ability to more accurately measure the clearances instead of using go-no go method. You can determine if the clearance is .225mm (.009"), .25mm (.010"), .275mm (.011"), .30mm (.012"), etc.

Even though the spec for exhausts are .010"-.012", you are better off shooting for .012" since the exhausts always want to tighten. Since the shims only come in .05mm (.002") increments, if the exhaust is at .010", change it to .012". If it is .011", leave it.