i have a 92 250x it has a hell of a tapping sound its been doing it for months now and it has not gotten any worse but it scares me i have adjusted the valves perfectly and it made no difference ive tested the commpression and its well within specs its should have between 79 and 91 lbs and mine has 86 the tapping does get faster when you rev it up but its not lacking any power does any one have any thoughts?

 

Try checking your Cam Chain tention I know that if the adjuster gets old or weak it will let slack in the chain just enough for it to hit the sides but the quad will run with it like that

 

I suspect it may be worn rocker arms. Not a biggie.