I recently had service done on my '96 Timberwolf 250. On our first ride of the season, we got about 3 or 4 miles down the trail when it got really hot and bogged down and stalled immediately when we stopped. We towed it back to prevent any further damage. Once back home and cooled off, it started up just fine. The oil level was okay. I took it in and the shop couldn't find anything wrong. We took it back out on the trail and the same thing happened. This time the shop got into the engine and discovered the bearing on the camshaft and end of the camshaft were badly worn with a lot of metal shavings. The shop replaced the camshaft, bearing, oil etc. and said it was good to go. On our very next ride the same problem occurred. Overheating and ceasing up. Towed it home again and took it back to the shop. They said the bearing and shaft had gone bad once again. They have no idea what is going on. They say the oil is making it through all the ports and flowing fine and has good pressure. But with the burnt bearing, shaft and all the metal shavings... Something, somewhere is obviously very wrong. I've been riding this machine for about 15 years now and have serviced it regularly and haven't changed my riding habits. Since the shop is perplexed, I thought I'd put this on the forums and see if any of you have thoughts on what the issue is? Help please