I just bought my first two 4-wheelers a couple months ago. One is a 2000 Warrior. The valves were really tapping. I have a Clymer manual and adjusted them twice. The tapping is better but still noticeable. I set the intake to 0.002" and the exhaust to 0.004. The feeler gauge seems to go in the gap easy until about 3/4 the way through as though the gap is not parallel. I set it so the gauge was really tight coming out but not sure if this is tight enough since they still are clicking some.

One other noise I have is when backing up and turning the chain makes a noise like something stressing or out of alignment. When I brought it home the first time the chain was really tight. After I loosened it these noises started.

Any help appreciated.

 

for your chain see if its binding on one of the sliders. The valve noise is normal because its air cooled and generaly a pretty noisy engine.