I have a 2004 650 with 4,000 miles. 2 weeks ago, while riding, the Cat developed a loud noise that sounds like the engine / transmission area. It sounded like someone hitting the engine with a hammer. The engine and drive train were smooth and quiet riding down a smooth road. Hitting bumps and backing off the throttle so engine braking engaged caused these terrible noises. I left the Cat 30 miles in the woods and went back with my truck to haul it out.

I brought it to the dealer and they replaced all 4 u-joints in the main drive line. All 4 were rusted badly with some roller bearings falling out in pieces. While apart, they replaced both rear wheel bearings which were sloppy.

After these repairs my Cat still makes the same noise - maybe a little less violent.

It really sounds like it's coming from the transmission area.

Anyone have a similar experience?

What did you find?

How big a job to fix?

Thanks,
Tom

 

It possibly could be your clutches, If you still have your old springs you may want to just swap them out just to see.

 

Thanks - great idea. I will look at the clutches and belt.

Tom

 

Checked both clutches and the belt - All were OK.

Problem discovered - The frame is broken completely off at the bend right above the motor on the right side. It looks like the pipe was cleanly cut in two with a saw just above the bend. There is a large plate welded between the two frame rails and both attachment points have broken welds.

The dealer is going to weld the frame and add stiffeners. I asked him to stiffen the side that's not broken too.

Tom