Yamaha calls for a valve clearance check at 600 miles. Won't hurt to do it sooner. Tdub needed some adjusting at 770, then again at 3000, 6000, 18000, 30,000, and 42,000. I tend to set valves at the loose end of the tolerance, because with valve seat wear they tend to tighten up. The exhaust seems to tighten up more than the intake, but when I need to adjust the exhaust I go ahead and do the intake, too. I still check them every 3000, though.