This is probably a ridiculous question since the testing requires a physical check, but are there "signs" that a valve(s) is out of specifications - I'm thinking something in the exhaust stream, idle issues, noisy valve train, hesitation, etc.? I know that on my Ducati, it is opainfully obvious when the valves need adjusting - bike sounds like and runs like crap and it happens at about 8K on the dot for me and my riding style (I guess I shouldn't complain as that gets me 2K past the factory service interval!)