Hey guys,

I found this forum in my searches and I figured I'd try posting here to see if anyone has any ideas.

We have a 2004 Bear Tracker 250 that overheated a few weeks ago. Ever since then, it is tapping extremely loud. I went through the usual troubleshooting and couldn't determine exactly where it was, except that it sounds like its definitely coming from the valve train. I did the old mechanics paper trick to check for a burned valve, and it alternates between blowing the paper out and sucking it in, which leads me to believe that it is a burned valve. However, today I pulled the head off and everything looks fine. I don't have access to leakdown test equipment, but I did the standard test, which is also discussed in the service manual, where you check the valve sealing by filling the intake and exhaust chambers with liquid. There is no leak. I already have a valve, so I'll probably put that on tomorrow for good measure. However, my question is what else could be the cause of the loud tapping? There is no question that it began when it overheated, so I have to believe that it was related to that. Other than the noise, it is running good. It has no power loss at all, and the only other symptoms I noticed were that it was backfiring occasionally and didn't want to idle when it was first started, which had never been an issue in the past.

I usually don't have a problem with engines, but on this one, I can't figure out what is wrong. My hopes are that it is actually the valve and it'll go away after I install the new one tomorrow, but I can't see how it could be bad enough to be making that kind of noise and still be sealing fine. I did search through here a little bit, but I couldn't find much discussion about my problem.

Thanks in advance.