I have read almost all the valve adjustment topics here, but none covered my issue.

A little over 2 years ago, I did a valve adjustment on my 2000 Trail Boss.

After I did this adjustment a couple of years ago, seems it ran fine. This ATV doesn't see much service. Well, about a year ago, I started it up, and went about my business in the barn, letting it warm up, and idle. I turned around and the barn was filling with smoke. I ran down to it, and it was pouring oil onto the hot exhaust. I couldn't see what was wrong, but I was afraid I had a cracked block.

Fast forward to now. I am just now getting to it (baby, move, same job but moved office, etc etc). I got it disassembled, and the valve cover was just sitting there, as if I forgot to put it back on.

Now, mind you, I didn't forget to put it back on. After all, I rode it several times after the valve adjustment.

What could have made the valve cover pop off? I'm pretty sure I got it on good, but I guess it's possible it was cross-threaded or something.

Could I have done the valves too tight or too loose and some exhaust pressure caused it to blow off?

What's going on? Help!

Larry

 

Must not of gotten the bolts tight, there is a tourqe spec for them, might try a little thread locker.

 

There are no bolts. It's just a cheap plastic screw-on cap that goes over the valves.

I put it back on last night after I posted the above. It went on tight. I see no damage, but I still wonder if a compression/fire stroke somehow blew it off.

Larry

 

I think I would be replacing that valve cap.Heat colud have weakend it and let it work off

 

OK, so I did the valve adjustment carefully and replaced the valve covers. I started it up and it sounded like crap. But it has sounded like crap for a long time.

I let it warm up and ran it up and down the driveway a few times. It sounded much better after warmup. I can't see any exhaust leaks, but that doesn't mean they don't exist. The exhaust system is original (from September 1999). But I think the crappy rattly sound is more internal.

Any thoughts?

Larry

 

does it have a timing chaing. have you checked the tensioner to see if its loose?

 

<div class="FTQUOTE"><begin quote>Originally posted by: eggenz7

does it have a timing chaing. have you checked the tensioner to see if its loose?</end quote></div>

No, it doesn't have a timing chain. At least not that I can tell.

Larry