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Rear axle and chain adjuster issues - a story


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Hey everyone-
Well this is sort of embarrassing but I figured I would share with the group so the same mistake isn't made. I had a bad experience with my rear axle after and chain adjusters after remounting my wheel after getting a new tire. This was my 4th time (or so) putting the wheel back on the FJ. I've done this before on many dirt bikes and other street bikes, so I thought I knew what I was doing.
 
Upon torquing down the nut, the opposite side of the axle starting eating into the softer material of the chain adjuster. Apparently the axle wasn't lined up flat against the chain adjuster nor pressed in all the way against the adjuster. See the picture below.
 
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I rode the bike like this for a month and a half, 90 miles a day. I thought that I had torqued down the nut/axle enough, but it was apparent there was still some slop. There would be a clunk when using the rear brake when first riding the bike. I also tried taking off the nut but after a half turn, it felt really soft, like it was cross-threaded. Gulp.
 
I did some searching and settled on buying the Gilles GYTR chain adjusters. They were reasonably priced from an eBay vendor. I also went and ordered a replacement axle, nut and washer from a local dealership since I knew the originals were not in working order. Once everything was received, I went ahead with the replacement.
 
This is where the fun started. It was really difficult to unscrew the nut, since it was in fact cross-threaded. Also, the axle head started eating the top of the OEM chain adjuster. It started shearing off the material from the top, due to the loosening motion. Eventually enough material gave way and the axle spun freely. My dad and I had to get creative in order to keep the axle from spinning while giving a solid base to continue to loosen the nut. For this, we laid flat a large open end wrench (over 1.5 inch) under the flat slide of the axle head and the drop outs of the swingarm. Didn't get a pic of this unfortunately. It fit snug enough to get a cheater pipe over a breaker bar on the nut and I put all my force into moving it. It came off eventually.
 
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What a mess. It was a relief to finally get the broken parts off. The new Gilles chain adjuster will not allow the same problem to happen in the future. The head of the axle sits in a perfectly machined space that surrounds the entire head. There is a slight draw-back to this particular model of chain adjuster, you can only screw/unscrew the adjuster a half or quarter turn with the little provided driver. Once you're set, it isn't a huge problem though.
 
You can see in this picture below, the damage leftover from removing the original axle. You can also see the new adjusters.
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Moral of this story: haste makes waste. Be sure that your axle is pushed in ALL THE WAY before torquing down. Also make sure the head of the axle is straight up and down against the OEM chain adjuster. I do believe it is a partially bad design or metallurgy, but also the blame lays with me. The system on the other bikes I've owned is a little more thought out, but the stock system should do if you're careful. A word of warning.
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  • 1 month later...
I might add, that if you grease the axle and don't clean the axle threads with a solution to remove the grease, or don't clean the threads inside the nut, that you should assume that the threads have grease on them and you need to reduce the torque 20-35%.  If Yamaha says 108 ft lbs, I would use no more than 85 ft lbs.
 
Reference: http://www.engineeringtoolbox.com/torque-lubrication-effects-d_1693.html

Ken, Candy Ass L.D.R. Sleeps 8 hours
(2)2005 FJR1300abs:  230,000 m
2015 FJ-09:  114,000 m (Replaced engine at 106K)

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Hey everyone- Well this is sort of embarrassing ...................................................the axle starting eating into the softer material of the chain adjuster. 
 
4779519.jpg
 
 
I do believe it is a partially bad design or metallurgy, but also the blame lays with me.

BTW:  I'm going with that this is a bad design, even though I haven't had any failures, the Alum. chain adjuster washer will be indented with proper torquing.   Mine looks Similar.  I'm looking for an after market unit now. :)

Ken, Candy Ass L.D.R. Sleeps 8 hours
(2)2005 FJR1300abs:  230,000 m
2015 FJ-09:  114,000 m (Replaced engine at 106K)

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  • 2 weeks later...
Toonbobo, takes guts to admit a mistake. First time I adjusted my chain I looked at that setup and said to myself 'make sure that left side is seated properly before you torque down the nut'. I hope I continue to remember to do so.
 
All that said, those adjusters you put on as a replacement are quite elegant looking and a much better design, IMO. Looks like a mod I may end up doing 'just because'. Thanks again for posting this.
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  • 3 weeks later...
Piotrek, I have these adjusters, they are made by a chap on the Facebook MT09 Tracer group, they are great quality and fit, you won't be disappointed! Quite a few people bought them in the group, all happy.
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Thanks for the link Piotrek, I've just ordered some as my adjusters are showing signs of damage and I want to catch them before it gets any worse.

Red 2015 Tracer, UK spec (well, it was until I started messing with it...)

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He just said later next week to me. I'm in no rush, just trying to preempt an issue I can see developing.

Red 2015 Tracer, UK spec (well, it was until I started messing with it...)

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  • 2 weeks later...
  • Premium Member
I just bought these. About as simple as they come and that's what I like about them... and inexpensive. Looks like these fix the flaw in the original design. We'll see... hope the seller ain't some shady character...'cause I used my kid's tuition money ;) . It's an equally worthy cause I say.
Just ordered a pair so I'll have them for my first tire change. 
Thanks for the link Piotrek.
 
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