Hi Ken ! One thing to consider is that sometimes valve clearances shrink. This happens when the valve face (seating surface) wears faster than the actuating hardware. It won't make any noise. By the time it gets bad enough to cause performance problems it's usually beyond just re-shimming. I used to have a V-65 Honda that I bought used. The previous owner hadn't kept up with the valve service. When I set them them to the correct clearance, (most of them were tight) they were noisy as hell. I ended up pulling the heads, then removing the valves. Most of them had carbon built up on the faces. I carefully cleaned it off then re-seated the valves with valve lapping compound and a suction cup stick. For the rest of the time I owned it the valve train was very quiet when set correctly. I checked the valves on my used 05' R3 shortly after I got it (16,000 miles) so I would know where I was at. Several of them were to tight. Since that time I have to shim a couple of them that had become to loose (57,000 miles now).