mfallavol

I finally got to the timing chain a few weekends ago. This time I also happened to pull out the chain tensioner guides and found that they were really chewed up. I'm hoping that this was the ultimate problem with why the timing chain broke this time around. Only time will tell. I opened up the clutch side last weekend and didn't see anything that jumped out at me. The primary clutch was more worn than I'd have liked and I'm going to replace it but I didn't see anything that would explain the sound we've been hearing. I'm hoping to get it all back together next weekend and then we'll see how long it lasts this time around.

That sounds like you have exactly the same thing going on down there as me. Interesting that it hasn't caused you any timing chain issues. I was kind of hoping when I fixed that noise in the clutch area it would solve my timing chain problem. Just FYI, I have another Bayou 250 (my daughters) which is a twin of the problem ATV and it has been running great with neither problem. Lets see who finds the time to tear into theirs first.

I'd be interested in what you eventually find. I bought my son a Bayou 250 that was a complete mess, no compression and lots of stuff missing. After replacing the broken cam chain, a bent valve and a damaged cam shaft, we got it running but it when you turn it off it sounds like something still spinning in the clutch area. He rode it for a couple of days and then it suddenly died with another broken cam chain. I fixed the cam chain, took it to a shop to see what they thought and they didn't know. He rode it a few more days and then pop, it went again. So now its grounded. I think there is something on that right side that gets caught and puts a big impulse into the cam chain causing it to snap. Anyway, it will have to wait until I have more time for it.

I picked up a 2003 KLF-250 for my son's first ATV a few months ago. It had no compression and overall needed a lot of work. To make a long story shorter, the major problems were in the head; mostly a bent valve. We got it back and working and he was enjoying it until it just died. Started back in to it only to find a broken timing chain. I figured it had gotten stressed due to whatever caused the bent valve so no big deal...so I thought. The problem is he was back riding it this weekend; probably has less than 4 hours on it since the timing chain was replaced and the same thing happened. He'd been riding it down the trail very gingerly, we stopped to chat and he went to give it gas and it gave a little 'pop' and died. When he hit the starter it was obvious it needed to be towed back. Got it home to find the timing chain is broken again. I really have no idea why. It runs fine when running but now I'm gun shy. Any thoughts and ideas would be appreciated. He's getting pretty bummed so I'd like to get this figured out. Just ordered another timing chain so we'll get back into it this weekend.