I have a 1997 Yamaha Kodiak 400 4X4. When I start the motor with the electric start, there is a loud clunk from the case. I took off both cases on each side of the machine and found no obvious problems. I left the case off of the clutch side of the machine and disconnected the power so that the engine wouldn't start, but would turn over. As I turned the starter over, the clunk was definitely NOT coming from the clutch side, primary or otherwise. Next, I put my hand on the housing that the starter gear goes into and without a doubt, the clunk was coming from there. It sounded almost like there were teeth missing on one part of the stroke, because the clunk was there on every revolution of the motor, but upon inspection, there were no missing teeth or any other type of metal fragments in the case. This problem occurs not only on starting, but on shut down as well. As the motor loses RPM, sometimes but not always, it will clunk as it's coming to a stop. My brother has a 1999 Big Bear 350 4X4 and it has the same sound, except it is much quieter. I am thinking it may be the one-way clutch slipping on the compression stroke and for some reason, grabbing when the motor is cycling down. It doesn't seem to have the same problem when starting with the pull-start, but it still clunks when shutting down. Other than this problem, the machine runs perfect. It's very quiet, has loads of power and is over-all a great machine. I'm just worried that this problem could turn into something more severe. Any help is much appreciated. Thank-you.

 

My brother is having the same problem with his 1998 Kodiak. Any ideas what's causing it?