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730
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4/7/2010
Location
Newark, OH, USA
Edited Date/Time
7/2/2020 7:21am
18 yz450f. It keeps happening when I’m riding. I tighten the axle nut, then snug the bolt against the axle block while tightening the lock nut. Anyone else have this happen ever?
You had the adjuster bolt all the way out against the adjuster block and you had the locking nut where it is now.
You the tightened the lock nut to the back of the swing arm.
If so, no I’ve never seen that happen. I don’t see how it could happen. Let us know if you find the problem.
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If the threads are ok and it's just backing off, completely remove it all and clean it making sure there is no grease or anti-seize on the surface where the jamnut contacts the swingarm. You only want grease on the threads inside the swingarm.
You have to get this solved because you can royally screw your bike riding like this. Seen this happen before and when the guy landed a jump it cocked the rear wheel hard to one side, tossed the chain, and ruined the cases.
This makes sure you have it straight and no slack.
Make sure its dead nuts on alignment wise. Other than that cant think of anything. Are your wheel bearings tight in the rear still? If they're shot youll have all kinds of issues back there.
Yea if youre tightening the axle first, youre 100% going to make it crooked from the torque required to make it tight.
Here's a tip I learned from a pro mechanic.
When you do your final torque of the locking nut for the adjuster bolt, spin the locking nut TOGETHER with the adjuster bolt, until the locking nut is tight.
So basically spin both the nut and bolt together for that final tightening rotation.
I don't know if this will fix your problem, but it prevents premature wear on both the swingarm and the bolt.
put a wrench in between the chain and sprockets and spin the wheel back jamming the wrench which will force the wheel forward taking the slack out of the axle.
These two operations above contradict themselves or no? set the tension then take the slack out of the axle?
I would have someone other than yourself complete this task and see if they come loose.
Either way, for clarity, this is how you should do it:
1) loosen the axel so it moves when you push the adjuster bold back, but doesn't slide around otherwise.
2) adjust the bolts to how you want them (probably by checking your chain). I typically do 1-2 turns on each side. Count the number. This is usually more accurate the little tick marks.
3) loosen the axel, and push the wheel up against the bolts by putting something in the sprocket / chain.
4) make sure you're aligned.
5) put a wrench on the bolt and another on the flange. Make sure the bolt does not move with the one wrench, and tighten the flange all the way with the other wrench. This is why one is 8mm and one is 10mm.
6) put pressure on the wheel to make sure the axel is against the bolts, and tighten the axel.
When you wedge something in the sprocket and turn the wheel until all the slack in the chain is removed, it will force the axle and adjuster blocks forward into the adjuster bolts. Hold it tight like this while you snug up the adjusters and also while you are torquing the axle.
FGR01 mentioned something important: you can really go down hard if your axle moves! I had a wheel go sideways on me off a hard landing. It locked up the rear wheel, bent the axle and ruined the rear hub and sprocket.
Pit Row
I seem to be having the same issue with my 2020 YZ250f. (10hrs so no excessive wear)
I have never had this happen to any of my previous bikes.
I am checking between motos, but this still happens sometimes while on the track to the point that the axle moves and binds but luckily doesn't lock up. This has happened 3-4 times now.
Seems like I have a slight but constant rear brake drag that I can't get rid of, and this happens on both my wheelsets. Disks do not seem to be bent. Not sure if the drag is caused by the wheel getting out of alignment a couple times, or if this is a normal YZ250f trait.
Any input or shared experiences appreciated.
Sorry to bump an old thread but I've been having this happen on my YZ250F now too and it's driving me crazy. So I did a search to see if anyone else experienced it. Any other solutions, any one has found? I even had new tires put on by a shop and it happened again, so I don't think it's the procedure of how I tighten the axle.
I had the same issue and made a new thread on it about a month ago (see here: https://www.vitalmx.com/forums/tech-helprace-shop/chain-adjuster-backin…).
Ultimately I just cleaned the bolt, nut and swing arm thread and ran them with no anti seize. I’ll have to check it for thread damage more regularly, but it seems to be holding more solid and hasn’t backed out so far. It seems common on the YZ-Fs, always the right side for some reason.
Ok cool. Ya I was just a little uneasy about the Loctite idea. So I bought a titanium bolt/nut kit. It arrives today. I will also put on some anti-sieze and hope it works. Thanks.
My Kawi does the same thing if I tighten the lock nut before the axle nut. I just tighten the adjuster first and I haven't had it come loose.
As mentioned, the procedure of how I tighten the axle was not the problem. Also the dealer recently had the wheel on/off (new tires) and it still came loose right after that as well. So unfortunately, was looking for another solution. Hopefully the new bolts work.
I thought the same thing. I switched up my chain adjusting technique and haven't had an issue since. It's worth a shot and I agree there's nothing wrong with how you adjust the chain, you just want the adjuster to not come loose.
I do the rag/wrench in the sprocket. Use the adjuster bolts to set the axle. Tighten the axle. Then tighten the lock nuts while backing the adjuster bolts into the block, so it's snug on the axle block. That's how I've always done it. If there is a step that I can do differently, then I'm open to try. Over the weekend my new bolts came. Threw them on and used anti-seize on the threads that go into the swingarm. So I guess we will see how it goes lol.
I do the rag approach, I know you won't hurt anything with a wrench, but it just feels super ghetto 😂
So do everything the same exact way except tighten the adjusters before you tighten the axle. I don't know why this works for my Kawi, but it does.
Fair enough. If it comes loose again, I will certainly give it a try. Thanks.
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