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Rear wheel shake while on centrestand

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Captain115, Jun 19, 2012.

  1. Hi everyone,

    So on the home stretch of repairing my housemate's 1988 Honda VT250F, and we've replaced quite a lot of stuff. But for the purposes of this thread, was have replaced:

    both sprockets, chain, rear tyre, wheel bearings.

    Anyway I had it up on the centrestand the other day, and had it in and out of first while I was playing around with adjusting the clutch. I noticed it seemed to have the tiniest of 'wobbles' I guess you might call it. Clicked it up through the gears, with the wobble getting more and more pronounced till 6th gear when it was shaking the bike really badly and I was worried it might knock it off the stand (at all time I had the clutch and front brake covered just in case).

    To describe the wobble in more detail, it wasn't all the time, maybe every 3ish seconds? It would sort of shake the bike, like as if the wheel was egg shaped and it would roll sort of awkwardly? Really hard to describe, I'll take a video over the next couple of days to properly show it.

    So I was coming (proverbial internet hat in hand) to everyone on this forum, to ask what would be wrong?

    Current thoughts:

    chain might be out of alignment (but seems stright when I look from rear to front sprockets along the chain)

    chain might be too loose/tight (but I've triple checked the chain tightness to manual spec)

    Wheel bearings might not have seated properly (but I swear they were pretty well in there)



    Wheel wasn't balanced when tyre was put on (but we took it to a professional shop for bike tyres so I assumed this would've been ok)

    Thanks for all the assistance in advance.

    Cheers,

    John
     
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  2. When the tyre was last fitted, was it properly balanced?
     
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  3. Hmmm well I'd love to say yes but we asked for a new tyre to be fitted and the guy said "yep $150 for tyre and fitment" so I assumed he also meant balancing. I thought that was like a customary service if you bought a tyre and got it fitted at a place?

    Anyway, do you think that's what the problem is? And will it be a problem when there is weight on it (ie actually riding on the road) or is it only when it's on the centrestand, unweighted, that it looks bad?

    Cheers,
    John
     
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  4. AFAIK a wheel should not wobble regardless as the bearing should not have any sideways play in it. maybe the bearing wasnt installed correctly? (and/or wheel isnt balanced)
     
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  5. I had a new front tyre fitted and balanced, Took it back and said it was vibrating, which wasnt there before,
    He said some times the balancing machine doesnt always work properly, Rebalanced the tyre, No more problems with it,
    And this was from a company that fits and balances bike tyres all the time, Specialises in bike tyres,
     
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  6. Call me cynical but I'm calling BS - I'd rephrase that as the mechanic saying "I can't be bothered balancing tyres and I save time and money taking that shortcut as only one in 10 complain"

    Those balancing machines are pretty precise, and they keep adding weights until the computer says it is perfectly balanced. I would think it is highly unlikely that the "machine didn't work properly"

    P.S. Even worse if that is what they specialise in
     
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  7. Ok so the current thought is wheel isn't properly balanced? So take it to a shop, get it balanced and go from there?

    Can any tyre place do this (Kmart tyre shop etc) or should it be a proper bike place? And roughly how much would it cost?

    Cheers,
    John
     
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  8. Chain slap because you're not loading it & it's a V twin.

    Give it a rev & see if it goes away. Cover the clutch.

    It's unlikely to be wheel balance at those low speeds.
     
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  9. They are very precise, But they do stuff up occasionally,

    BS, I stood there and watched him do it it the first time, I stood there and watched him do it the second time.
    No, it hadnt thrown a balance weight either.
    And he does racing tyres all the time as well.
    Thats also the first time it has happened to me, I have had quite a few sets fitted by him, And Always faultless before,

    He is very good at what he does. And I will still go back there,

    And you have never bought a brand new bearing and its rooted, I have,
     
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  10. I'd try riding it and see if it's a problem on the road. I've run many bikes on the stand and a lot of them have exhibited various odd behaviour, simply because running unloaded with the back wheel in the air is not a natural situation. If the problem goes away in the real world of riding, then it's not a problem.

    If you must have perfect behaviour on the stand, try applying a touch of rear brake to simulate some rolling resistance and keep the chain loaded up.

    Something worth remembering is that on a bike as old as the VT, there's a good chance that one or both wheels are no longer circular or laterally true. A quarter century of potholes, kerbs and inexpert tyre fitting tend to do that. Again, it's not really a problem if it doesn't significantly affect the riding experience.
     
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  11. I'd re-do the wheel bearings.

    they may not have seated properly, or you may have hit the centre of the bearing whilst installing it.

    Before installing the new bearings, throw them in the freezer for a couple of hours, then use a heat gun to heat up the hub housing, bearings will almost drop into position; remember to only tap the outside edge of the bearing.

    For the sake of $20-$30, I'd rather have peace of mind that the wheel isn't going to lock-up at 110kph.
     
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  12. while changing all the bearings and stuff did you check your cush dampers/ drives ? or maybe you left 1 out by accident. in the same area, did you check the amount of brake lining you have left on the steel drum, mine are showing the max I/D of 141mm, do you know the "new" specs?
     
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  13. If any lateral movement in the wheel then check the bearings. If chain is really loose while up on the stand it could be slapping about but I wouldn't think enough to violently shake the bike.

    Is the wheel out of round? Was it crashed? Axle tight?
     
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  14. #14 jstava, Aug 18, 2016
    Last edited: Aug 18, 2016
    Consider that the sprocket may not be round, or the chain may not be accurately sized along its length or a combination of the two. To check this, slightly over tighten your chain and watch it closely as you turn it BY HAND through half a dozen revolutions or so of the chain while the bike is on the centre stand. Watch and feel for any variation in tension. If it binds, stop. You don't want to unduly load your output shaft over a tight spot.

    I bought a cheap new sprocket once that was so far out of round that it was unusable. I doubt very much you'd get a motorcycle chain that that was "longer" along part of its length than another. It is possible. (what isn't?)

    Tyres are also a little notorious for either being a little out of round or much more often, inconsistently seated in the rim.

    Little things that are a little bit out are also amplified when run at near real speeds on a stand. (is this a good idea? No. What happens if it comes off the stand? ) A little shake, shakes the bike, which in turn shakes the rotating wheel amplifying the effect of what is causing the shake., and the overall shake oscillates due to the source of the shake getting in and out of synch with the sympathetic (harmonic?) shake of the bike.

    In order, i would look at the seating of the tyre, the chain, as described above - for an out of round sprocket, wheel balance (I can always do better at home than the shops do), based on the principle of checking the easy things first.)

    If I was certain my assembly was correct, I'd look no further, but consider the wheel bearings at the next service - remove the chain and brake pads and listen to it while spinning the wheel on the stand. Any crunchiness at all, coarse rumble or lateral movement (pull one side of the wheel while pushing on the other), puts bearings in the frame. Anything other than smooth bearing noise (they do make a sound, but to listen to them, you need to eliminate chain noise and the slight scrape of disk pads to listen to them) or wobble-like movement would have me looking at the bearings. One can often tell when a bearing is starting to go by looking at the grease. It turns grey due to metal in it. This happens long before they fail outright (that's a thrill) You often don't need to remove them to confirm that they are OK. A dig with an icy pole stick can remove a little sample of grease so you can get a look at it, if you can reach the bearing.

    Wheel problems? Definitely a possibility. People can hit potholes and objects and hamfisted tyre mounting can damage rims. Tape an icy pole stick or pencil to the right side of your swing arm so it very nearly contacts the rim. Turn the wheel by hand - you will see if your rim is true. This is just like checking bicycle wheels for true.
     
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  15. four years not to shabby for a resurrection :)
     
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    • Funny Funny x 2
  16. I'd tend to agree with jstavajstava it's not really a good idea to run them up through the gears on the centre stand, if the wheel balance is fine, tyres good, chain and sprockets true then one other possibility exists and on a machine with that age it could well be that the swing arm bushes and bearings are shot, on the stand see if you can move the swing arm laterally at all, any sidewards movement and time to replace.
     
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  17. When you check the wheel bearing and swingarm don't just push and pull them, give it a bang with the ball of your hand and feel with the other . I have found knock or small movement that wasn't there with pushing but showed up with a bang.
     
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    • Agree Agree x 1