Back to the funny miss, sporadic knick knock, after warm up. '85KRS, just turned '84K, posting before that valve leaks may be allowing gases into pipes makes said noises. Leading to reconditioning an extra head for replacement.
Before doing anything I think a lot about stuff, and it helps to have an extra scoot. So, I did a leak down test with compressed air on each cylinder in turn using 100psi at top dead center compression. Cold, no leaks into crankcase or exhaust pipe. Hot? Same deal. This old K doesn't, far as I can ascertain have a leaky valve or valves!
I'm not an expert mechanic, don't have a scope thingy I can snake in there, just that there were no perceivable leaking sounds or rushing air.
Now on to other stuff, went to the baseline of the bike's condition when I received it. So today reattached the pressure switch that signals to the ECU which according to somebody modifies the midrange throttle response. Went for hot lap or two. No difference. Same old same old. Not to worry, cuz it's becoming clearer that there must be either an intake leak problem which doesn't show itself until the engine gets hot, or, maybe, I'm still thinking.
Doing one thing at a time, bound sooner or later to hit on the problem. Here's the plugs, they all look the same, tan on the porcelain.
