Aftermarket XR650L drive chain tensioner?

Has anyone ever seen an aftermarket system for drive chain tension? I think the stock system is the WORST design I have ever seen!! I have looked at factory diagrams so I know it is set up right but I keep finding the right side rotating loose after riding? I have been having to use vice grips on both tensioners to hold them in place after adjusting the chain, prior to re-tightening the axle nut? The right side especially keeps trying to rotate loose every time I try to tighten the nut! I have even tried oil between axle but and washer to try to keep it from rotating.... I just got back from Colorado where I did tighten it a couple times during my week there, and once again found the rear wheel cocked and right tensioner rotated loose....

Right side..

ImageUploadedByThumper Talk1439156233.451879.jpg

Left side..

ImageUploadedByThumper Talk1439156353.265379.jpg

Axle nut is supposed to be tightened to 65 ft lbs.


If stuff back there is moving around I would check things out for damage.

Never had one come loose.

I noticed your axle is in the opposite direction as mine. The wheel and bearing rotation could potentially cause yours to loosen.

Probably worth trying to flip it and see if it helps.

According to Honda diagram mine is correct?

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Might help, I'll look at my manual as well! I'll try anything at this point!

First get a new nut, it is a locking nut. Then adjus your chain tension, setting the snails against the posts on th swing arm and snug up the nut. Then roll up a rag, hold it on the underside of the upper part of the chain and roll the rear wheel backwards to pinch the rag between the chain and the chain wheel. This will hold the snails tightly against the posts so when you torque the nut to 65 ft/lbs nothing moves. If you are doing it correctly your nut and adjusting snails will not loosen up.

Thankfully the 650R doesn't have this set up. I notice the DRZ400 Suzuki has a similar setup.

It has nothing to do with the chain adjuster design, you are doing something wrong or some parts are damaged and need replaced.


As far as you doing something wrong, that would be hard to do. There's really nothing to do but loosen the axle, adjust the chain, then tighten the axle to the required specification. It looks like all the parts outside of the swingarm are correctly installed. When adjusting the chain, a light kick to the rear of the tire will help push the axle forward, against the chain adjusters.



The direction the axle is installed is fine, that's not the problem.



You need to check the wheel bearings and make sure the spacers and brake caliper bracket are not damaged. If someone changed the bearings and left the internal spacer out, that would definitely cause the bearings to bind and quite possibly rotate the axle while riding. If the bearings are bad, they could also bind and cause the axle to rotate.

The nut is not coming loose I don't think? And I tighten that baby down plenty! That's usually when it tries to rotate on me, that's why I use 2 small vice grips on the snails, to keep them from moving.

I have always hated this design on any bike, with nothing but a swift kick or a boot to hold the wheel against the snail detents they at LEAST should be deeper more positive detents!

I was really really hoping someone knew of a conversion system to make this a more reliable system... Wish I was a machinist at this point... I will never trust this design..

In Colorado we were doing some extremely rough rocky passes and I imagine some of the rocks and aggressive braking on the downhill side are what jarred it loose?

It shows just the opposite in the service manual diagram. It doesn't detail it in the instructions. I'd give it a try.

My HONDA factory service manual shows mine is setup correct, not sure what manual you are looking at?

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Edited by Woody469

The same one you are.  I'm (obviously) confused.


I had to take another look at my bikes to be sure my axles were actually in the opposite direction as yours and they all are.  Even the Harley, which uses a non-notched snail adjuster system to tension the belt with a non-locking nut.  None have ever been an issue. 


I guess I'm totally backward.  Not surprising at all, I don't even trust myself sometimes...



Edited by hollerhead


I used to have a kdx that had that type of adjuster. I used to put it in gear and rotate the tire to pull it snugg against the adjusters then tighten down the nut.

I wonder if someone replaced the wheel bearings and didn't put the center spacer back in?

Are your swing arm bearings loose? Put up on lift n check every pivot/bearing spot for any odd movement! The lock nut should be bout 65lbs i think, but also do not overtighten cause that can cause damage also! Is the threads or locking axle nut stripped?

Lol, I like your name by the way hahaha

I can't imagine any bearing replacement or anything because I bought it used with 2200 miles on it and it still had the stock tires on it! It's about to hit 9000 and I haven't replaced anything involved yet! I doubt the rear wheel had even been removed to tell you the truth... I guess I'll just wrench that nut down tighter but I really think this is a poor design to begin with... I don't want to over tighten at all!

Lol, I like your name by the way hahaha

Had it forever LOL....

...I really think this is a poor design to begin with...



You can always switch to a swingarm with adjustment bolts, then deal with seized and broken bolts, longer adjustment times and no quick change rear wheel.

You can always switch to a swingarm with adjustment bolts, then deal with seized and broken bolts, longer adjustment times and no quick change rear wheel.

If only I knew a direct replacement swing arm at decent cost I would totally swap it out at this point....

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