Help me diagnose my miss over 4500rpm.

AAndrews said

Wow, great explanation and makes a lot of sense. Also seems to be a straight forward procedure that costs relatively nothing to do. Cley did your miss start occurring before or after the high rpm buzz? As well AJ/FormS , should you also see discoloration of the sparkplugs in the affected cylinders ?

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That's an interesting question. IDK the answer. I became a motorcycle mechanic in 94, after I made my decision for Christ. God gave me a new vocation. So I haven't worked on a whole lotta autos after that. Motorcycles are mostly DOHCs since IDK seems like forever now. And they rev 10,000 to 14,000 and don't have hydraulic lifters, for the most part.
But I have experienced lifter pump up with teeners, and SBCs, and other pushrod hydro-engines. Just never thought to check the plugs,lol. In fact I had a 340 once that would float the valves at 5500; shocked the chit outta me the first time it happened. Springs solved that. My teeners used to do it all the time, so I just starting shimming the springs or swapping to stronger ones. I guess I couldda shifted sooner, but that ain't my style. I threw a few bent valves away before I started shimming the springs.
But never looked at the plugs.