I am putting together an NSR 250 and I have a few questions about the exhaust valve.
- when I install the cast (iron??) exhaust valve into the exhaust port they recess as they should into the recesses in the top of the port. When I install the square shaft that opperates the valve(s), they seem to bind up some and one cylinder then doesn't recess beyond the timing edge of the exhaust port. Can I grind a portion of the valve away or is it coated/treated in some way that I will compromise it? I have been working with the cylinder/exhaust valve assemblies dry/no oil up to now. Perhaps it will get better when lubed? What lube is proper for the exhaust valve?
I should mention that the cylinders have recently been re-nic-a-silled.
Mark
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