I just checked/adjusted the valves on my 02 250F. It had about 50-60 hours on it.. exhaust side was in spec... Intake valves were tight... I went to smaller shims and re-assembled everything, I'm no mechanic but all went well. The bike was becoming very hard to start cold... Now it starts with a half hearted kick COLD. Very glad I done it.. I think alot of people avoid checking the valves because it sounds complicated it was easy. Adjusting took a little thinking on the shims.. but not that hard. If you havn't checked your valves check them now before it does more damage. I don't personally believe in checking them after the 1st 3 hours ... I think the bike will tell you when they need checked so to speak.. just be sure to listen.
