My Fazer (2001) has some 60,000 kilometres. A mate who is a mechanic says those figures are probably lower, like 40,000, judging by the bike's condition (fiddling with those numbers before importing or reselling vehicles is a usual thing here).
Now, Mr. Haynes says something like 40,000 kilometres between checking valve clearences. My mechanical mate says to just leave it until I hear valves rattle. Doesn't want to take my money for just opening and closing the engine back (most local mechanics will charge for checking clearences WITHOUT even opening the bloody engine).
How often do those valves get out of line? What are foccers' experience? Should I just leave it, or check every 20, 40, or 80 thousand kilometres?
Bit of an off topic: about cam chain. It does rattle a bit. The same mechanic mate said to leave it until it rattles a lot louder, this is just OK.
Same for carb balance: leave it until it really gets running really rough.
What do you people do? I've never done any of these things, would go for DIY, but not before it really needs doing.