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Clunk noise after jbs sheave

1407 Views 11 Replies 3 Participants Last post by  RedRocket
Ok so to start I will say all work was done correctly and double checked I cleaned my secondary and primary sheaves and added a jbs gold spring, wet clutch slugs, and a jbs extreme sheave with 14 gram od weights I noticed on my first ride with the new set up that it makes a single "clunk" noise when I let off the throttle quickly it is more noticeable in low but can definitely feel and hear it in high. Yes my engine braking is working as is should. I put the wheeler on jack stands and ran it in high and low and the noise is gone but once on the ground again you hear the clunk that sound like it's coming from the clutch area. Any help will be appreciated I have not been able to call jbs yet.

2016 Grizzly
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Might be the belt making contact with the outer CVT cover upon deceleration. Pop that cover off to know for sure and if that is so, I wouldn't worry about it. It will do that until enough is worn off and it doesn't make contact anymore. There's what, 12 or so bolts to remove the cover and check it out?
I rode last night for 4 hours, you think that would have been enough to make a grove also it does it at any throttle position not just wide open.
Yeah, it took a while for mine to stop making that noise and I also thought the same as you. Pop that cover off and take a look to see if it is rubbing. Should be pretty easy to identify the area if it is happening. That way if you know it is just the belt rubbing on the cover, might put your mind at ease.
Ok will do tomorrow and let you know. So yours was doing the same thing?
Yes, and it did it for some time. I would say probably for over 500 miles but it did not impact the belt or wear thru the CVT cover but did "groove" the cover near the secondary.
If you aren't running a shim I doubt if the belt is rubbing. The Just Because I Said cut doesn't add that much to the belt high. Using the gold spring and the 14's causes hard backshift. That is most likely the cause of the clunk. My 700 primary has a my 3:1 face shave with 20's and a purple spring clunks.
For whom it may concern I belive the issue is the rear diff bolts have come loose enough to woller out the holes in the diff so I ordered a Turner cycles diff brace and will see if that takes the noise away I was ordering one this week anyways so we will see
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I would definitely repair the frame mounting holes before adding the bracket.
I did a temporary fix on a friends Griz before a ride this past summer. We install some copper washers between the diff housing and the frame mounting tabs. This locked the diff in place until the owner can get a proper repair this winter.
I don't really like the bracket as it uses the bolts on the top side of the diff. It seems that there is a possibility out those bolts and maybe cracking the diff housing.
Torquing the OEM bolts a couple times a season would help avoid this problem.

Post back if this helps the clunking.
Noise has stopped after the diff brace all is good I fixed the holes on the frame and she is tight now I am very happy
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Thanks for posting back.
Yep, good to understand what the issue was.

Very strange though that the clunking was coincidental to you doing some CVT work.
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