I have a 04 YZ450F, and have only adjusted valves once...2.5 years ago. I checked them again this morning. The middle intake valve is .152, maybe .153. Should I adjust this valve or just keep riding and check again after more riding...or until I break something else that causes me to tear the bike down. I was wondering if tighter side of specs is better than high side since if I re-shim my new setting will be .102 or so. If you guys think I should adjust, are there any special tools required? It seems like I had to modify a tool to be used on the tensioner but cant remember.