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How to tighten rear axle castle nut without chain adjuster moving

Discussion in 'The Garage' started by chopplebrains, Aug 1, 2020 at 10:05 PM.

  1. chopplebrains

    chopplebrains XS650 New Member

    Hi folks - I'm new here and just got my first xs650 about a month ago. Pretty new to working on motorcycles, but having fun learning - I'm hoping this is a simple problem that people can advise me on.

    I'm adding a TCBros tail light/license plate kit, mounting it to the rear wheel axle. I removed the castle nut (it was barely on there, I was surprised at how loose it was), got the mount on, and tightened up castle nut. I looked up the torque values and started tightening with my torque wrench - during this process the chain adjuster rotated down due to the rotation of the castle nut and bent the chain adjust bolt (see pic). Bummer. So I sheared that bolt off, and drilled + pounded it out (i.e. I got the bolt off without removing the axle/chain adjuster - no small task to cut the bolt on the inside of the chain adjuster). Got a new bolt from Mike's XS, and back to it.

    This time I decided not to have the chain adjust bolt tightened in and to also use less torque (was shooting for 70ft lbs this time thinking that might be tight enough based on some threads online, or maybe a little less with some locktite).

    As I'm tightening the castle nut though, I have the same problem of the chain adjuster moving (and license plate mount) as I go. It isn't super tight even and nowhere near 70lb of torque. I've tried putting a jack under the license plate mount/chain adjuster to hold those from moving while I tighten, but that's pretty hard to do (the bottom edges aren't aligned on those pieces).

    I feel like I'm missing something. How do you tighten the castle nut without the chain adjuster moving once you start to really tighten the castle nut? How tight should it be? I read just make it "real tight" and then rotate a bit more to get the cotter pin in - but even trying to get it "real tight" the bracket/chain adjuster rotates on this sucker.

    If I do this with the chain adjuster bolt tightened up, then the bolt will likely bend again (that was a nightmare to fix the first time around). I haven't been able to find anything online really except for a thread on this forum on a similar topic but the answer diverged into grinding the frame, getting stronger bolts, and the guy ended up just selling the bike it sounded like. I'm hoping I'm missing some mechanic's trick or technique which someone might be kind enough to explain.

    Thanks for the help!
    (image of the bent chain adjuster bolt from the first time I tightened the castle nut - don't want this to happen again)
    bentBolt.png
     
  2. bikefreakjon

    bikefreakjon XS650 Enthusiast

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    70 foot pounds is probably more than necessary and definitely don't use loctite.

    Put a dab of Grease under the nut so that it can turn against the chain adjuster smoothly and then wedge a big screwdriver or something between the sprocket and chain and rotate the wheel to pull the chain adjuster forward all the way up against the swing arm hard.

    That should do the trick!
     
  3. chopplebrains

    chopplebrains XS650 New Member

    I’ll give this a try - thanks for the suggestion! Since I’ve never done this before, and it looks like I’ll get to learn about adjusting chains/making sure wheel is aligned now, to help me learn - can you say what the point of the screw driver is? I totally get the grease suggestion (feel silly for not thinking of it before - great suggestion)

    cheers
     
  4. bikefreakjon

    bikefreakjon XS650 Enthusiast

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    When you run something between the rear sprocket and chain, it takes all the slack out of the chain and pulls the adjuster in tight to the swingarm so it won't spin.
     
    chopplebrains likes this.
  5. 5twins

    5twins XS650 Guru Top Contributor

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    Your chain adjuster looks squashed flatter than it should be. Do you have an aftermarket hardtail or a different than stock swingarm? I ask because many of the aftermarket hardtails have axle plates that are thinner than the stock swingarm one. This squishes the chain adjuster like yours seems to be when you tighten the axle, unless you add a washer under the outer side. I think you may need and want to do that.

    If you look at the end of your chain adjuster bolt, you'll see it's tapered. The end of the axle plate should have a dimple drilled into it for that tapered bolt tip to fit into. This effectively locks the adjuster in place as you tighten the axle and keeps it from spinning. If you have no such dimple, or a very small one, maybe you can make it a bit bigger and deeper by drilling into it a little. I'd use a drill bit the same size or slightly larger than the adjuster bolt diameter and don't go very deep, just ''dimple" it. Just drill in as deep as the angled tip on the bit allows.
     
    Paul Sutton and bikefreakjon like this.
  6. bikefreakjon

    bikefreakjon XS650 Enthusiast

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    Except it won't lock in unless his chain is tight...
     
  7. 5twins

    5twins XS650 Guru Top Contributor

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    ..... which it should be after adjusting and then proceeding to tighten the axle nut. I've never had the adjusters spin like that after adjusting the chain and then tightening the axle nut on any bike I've ever owned. It would seem a properly adjusted chain is tight enough to hold the adjusters "locked" in place. But, this appears to be a custom set-up so I guess all bets are off, lol.
     
    nj1639 and Paul Sutton like this.
  8. bikefreakjon

    bikefreakjon XS650 Enthusiast

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    I think he just wasn't watching what was going on because he was too intent on the torque wrench!
     
    Paul Sutton likes this.
  9. bikefreakjon

    bikefreakjon XS650 Enthusiast

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    I had a Harley guy bust my balls for not using a torque wrench on his axle nut the other day..
    I told him it was tight enough, he insisted and when I checked it was within a couple pound feet of the spec.

    Just cause you are using the right tool doesn't mean you are using it right.
     
    Paul Sutton and Bushyeyed1 like this.
  10. 5twins

    5twins XS650 Guru Top Contributor

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    Speaking of which, I do use a torque wrench on many things, but not my axles. First, I feel that rear wheel spec is crazy tight and second, it's given as a single number spec. How does one tighten to that single number spec and then get the cotter key in? Right, not happenin', lol.
     
  11. bikefreakjon

    bikefreakjon XS650 Enthusiast

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    No kidding. Tight enough is tight enough, if it slips tighten it more next time.
     
    Boog likes this.
  12. chopplebrains

    chopplebrains XS650 New Member

    Lots of good stuff here - thanks for the discussion.

    The engine is from a 79, frame from an 81 - seems to be a mix of stock parts and some custom stuff. I added some picks with the castle nut off below. Originally, I just wanted to put a license plate mount on - and naïvely believed I could get away with that without having to bite off learning about chain adjustment, or adjusting anything else - was supposed to be simple :). At this point, the wheel has been moved, chain tension has been affected, wheel alignment, etc. Well, time to learn how to adjust and tighten a chain I guess, needed to know that at some point for maintenance, so here we go. When I bought it, everything seemed to run fine (though I never measured free play on the chain).

    @5twins - I think these particular parts are stock - the bike isn't a hard tail, but the back of the frame was chopped and lowered just a bit I believe. And yes, there's a dimple in the swing arm for the chain adjuster bolt (it has a nice scrape and a tiny bit of shaved metal now from where the previous bolt got bent, and then further moved around as I was trying to get it off). The dimple is still there though so I don't think I'd need to drill. Even with the dimple and bolt in, the bolt won't be strong enough to hold everything under the torqueing (worried even if I do less that perhaps it will bend at this point, but maybe not). And, based on the bit of reading I've done on adjusting chain and rear wheel alignment, it seems like these things are all related - and you may have to set them, and then readjust as they seem to affect each other. So I'm not sure about sliding wheel all the way forward/back and tightening castle nut - in that case, I'm not sure how I'd achieve the right chain play (again, never having done it before, just watched some youtube videos at this point). It sounds like the chain being tighter helps hold things together and doesn't rely solely on the adjuster bolt to keep everything tight. And to note - it was WAY harder to get the chain adjuster to rotate the first time I was putting that bolt back on that it is now. Now that thing will rotate easily - so I've clearly loosened up the entire system.

    @bikefreakjon - yeah, I was pretty focused on the torque wrench as this happened - but I did see (or thought I saw) something shift. Couldn't tell what. Tried to tighten some more, saw it again. Turns out it was a combo of the wheel adjusting slightly and also the bolt starting to bend (it wasn't noticeable at first) - the bolt bending happened a little at a time then all at once. I was pulling like hell on that torque wrench too - not doing that again.

    @5twins - the manual I have is a Haynes and says the torque values are indeed a range - 87 to 130 ftlbs for the D, and 108 for the other models/letters that are appended on (the D, E, SE, F, G, H, etc - alphabet soup) (not sure how to know which one I have even). I was just shooting for 90 originally, but will be way less next time around.

    So I think the strategy now is to get a couple extra tools to help me adjust my chain and make sure it is aligned. Go through that process from square one, add a bit of grease between the castle nut and stuff I don't want to rotate, and go easier on the torque next time around.

    Here's a few extra pics of the parts to provide more context:

    topView.png
    dimple.png sideView.png
    withLicensePlateBracketOn.png
     
    bikefreakjon and Boog like this.
  13. Paul Sutton

    Paul Sutton Sprained Ankle Top Contributor

    I wonder if that bent adjuster bolt is non-original, it seems to me it does not have enough taper at the end to lock into the dimple. I have never had an issue with tightening the rear axle and suspect all these issues will go away when the adjuster bolt fits that dimple correctly.

    Adjusting the chain needs the same tools as used to tighten the axle plus two spanners for the chain adjuster bolt and lock nut.

    I liked 5twins point about torque settings and cotter pin alignment. It reminded me of the chain adjustment instructions where you need to have the rider seated to make the measurements which is a bit tricky on your own:

    Chain.png
    (Click Photo to expand)
    The adjustment does not work well on the center stand because the chain tension changes when you drop the bike back down on the suspension. I usually just make sure the chain does not flex enough to hit anything down there. Then there are all those 3 handed jobs...
     
  14. GLJ

    GLJ Never go faster than your guardian angle can fly. Top Contributor

    Can you get a clearer pic of the adjuster. It looks like it had "bumps" on it where the nut hits. It needs to be smooth or the nut will try to turn it when being tightened.
    upload_2020-8-3_7-11-58.png
    I don't know if it's the camera angle or me. The axle looks bent, the swingarm looks like it may be collapsed and the threads at the end of the axle look chewed up.
    upload_2020-8-3_7-17-27.png
    You really should have the locking tab washer under the sprocket bolts. They have been known to loosen and back out.
    upload_2020-8-3_7-19-28.png
     
    nj1639 likes this.
  15. bikefreakjon

    bikefreakjon XS650 Enthusiast

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    Wire brush and clean those axle threads, that will help it clamp harder with less effort.
     

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