Viper chain case explosion

Y

yogi

New member
Joined
Sep 27, 2004
Messages
23
Age
54
Location
Maine
Got a question for you guys. Do you routinely check the nut and bolt that hold the top and bottom drive sprockets on? Once a year or at all?
Reason I ask, blew a huge hole in my chain case. Thought I just popped the chain, even though I change the oil every year and check tension often. BUT, after taking it apart I found the nut that holds the top sprocket on was hanging on by one thread. Just touched it with a wrench and it fell off in the belly pan. And, the bolt that holds the bottom sprocket, the head ahad snapped off it on the shank, just under the head. And the chain was in several pieces in the bottom of the remaining case. I am assuming the top sprocket moving all over the place caused the destruction.
I have never been into the chain case, 2002 with 5600 miles and well serviced.
 
yea thats definately unfortunate, not too much you can do to prevent that, you would never expect it. The top nut must have come loose and put all the stress on the bottom bolt, breaking that, and breaking up the chain because of the poor alignment. Maybe would want to put loc tite on the new stuff for some cheap insurance. They come with loctite on the bottom, but i dont think on the top.
 
I've never seen a nut come loose that had been tightened at the factory. And if it did and the top gear was loose while running, theres no doubt why the rest happened. Also, if you were adjusting the chain with the cover on by feel and the top gear was loose the chain at that point was way too tight and just aggrevated the situation. I never adj a chain with the cover on, ther's no way to make an accurate chain adjustment by "feel".
 
My bro had a similar situation last season. It started out with the bearing and pillow block on for the driven clutch on his 02 viper. The bearing froze up warping the pillow block allowing the jackshaft to wobble real bad. When all of this was replaced we realized the nut had worked it's way loose in the chain case for the top gear. We caught his before major damage was done in the chain case. Check that bearing on the opposite side. Yamaha replaced everything under his warranty. Thank you Yamaha! This happened when the sled had 6,000 miles on it. I became curious about it and started looking at my 02 viper and my jackshaft was real loose as well and Yamaha replaced all my parts too. With the help of my dealer our investigation found that the three lock nuts that hold the jackshaft in the bearing did not come with loctite on them from the factory. They backed out from vibration wearing out the jackshaft. My viper also had 6,000 miles on it.
 
What is your suggestion on how tight to make the chain. And it sounds like loctite on the top nut and bottom bolt is cheap insurance.
 
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