The OBSERVED Valve Clearance thread

[Inhouse Bob]

This discussion leads me to question my own situation. I generally wear pretty good ear protection and the engine sounds like the proverbial sewing machine all the time. But once in a while I will forget the ear plugs and everything is louder. That's when I notice that under pretty good acceleration I hear distinct ticking from the engine. It runs as it always has with no discernible difference over time. So, is this the injectors doing their thing or valves rattling around? It's got 15k miles on it, mostly casual riding though I do prefer to keep the revs elevated (3500 to 4500 RPM are normal, I guess).
Or maybe I should just put my earplugs back in