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The tappety-tappety noise is a worrisome annoyance that I have, too. The first time I ever noticed it was when I learned that my oil pressure idiot light was burnt out, and that the oil I had decided to use in the last oil change sucked.

Basically, I'd used that crappy oil up, and my crankcase ran so low in such a short time that my oil pump started sucking air - viola, inadequate lubrication. I think I diverted my ride when I heard the noise directly to the shop where we discovered the problem.

That was back when the bike was still pretty new to me and I was experimenting with different oils - and it only had about 8k miles on it.

Now I have more like 38k (or is it 48k, now I can't recall) and I'm hearing it more regularly, even with fresh good oil. But, the oil selection does seem to make a lot of difference.

Usually, I've been using 10w50 synthetic and liking it. Still, I have been hearing some of that sound. However, a couple weeks ago, my shop talked me into trying 20w50 synthetic. They claimed that the 10w50 would be getting burned up too quickly in my bike given its mileage.

Hogwash, methinks. I think what that means (unless I'm deliriously not remembering my oil physiochemistry properly) is that those guys don't really understand the viscosity designations. The oil should only be behaving as 10w oil when the engine is cold and needs thinner oil anyway. It should begin heating and pass through the 10w range quickly, ultimately rising to full operating temperature and behaving at 50w for most of it's operational time.

Sure enough, now with that stupid 20w50, I'm hearing that tickety-tickety steady with every startup for the five first full minutes of operation - which is apparently how long it takes for the engine to heat enough to thin 20w oil enough to pump adequately.

Unless the engine is really drastically worn, or you are in the deep south starting the engine consistently in 100 degree weather, I really don't see any value whatsoever in using an oil that has a lower number above 10w. I think the more important number is the higher number which, in my well-used engine is definitely preferred at 50w nowadays.

I suspect that the 10w40 vs 20w50 issue is because of the original dyno oils being unable to span all the way from 10w to 50w. The delightful synthetics, however, don't share that limitation and I am now a huge fan of that 10w50 synthetic. I've also experienced very good shifting behavior on the 10w50 synthetics.

I vaguely recall dyno oils briefly coming out (perhaps a first coming out) in a version that attempted to span too much range (was it 5w40?) that quickly became widely reviled and vilified (and maybe even recalled or discontinued, though perhaps later reissued).

Marpesia