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Odd vibration - chain, sprockets, wheel bearings?

Discussion in 'Technical and Troubleshooting Torque' started by Bravus, Aug 7, 2008.

  1. The Bandit will be going in for a major service in a couple of weeks when my tax return comes through, so this will get sorted then. But I'm kind of having visions of them saying "WTFBBQ! You were this close to exploding into a million pieces!"

    There's an odd vibration in the footpegs of the Bandit (that is, that's where I'm feeling it, not in the bars or the seat) when just cruising along. It's nowhere near the frequency of the engine - maybe more like regularly every second or 0.8 seconds or something. What it feels like to me is an unlubed chain, but the chain is well lubed. There's no really obvious frozen links or anything like that with the chain, but I guess that's a possibility. I assume if it was the front sprocket it'd be more frequent than that as well, but there's nothing obviously weird about the back sprocket. I've popped the bike up on the centre-stand and spun both wheels and there's nothing that seems like a notchy wheel bearing, at least in that no-load situation. Any experience that might suggest a solution? (I'm budgeting for sprocket and chain at the service just in case - apparently they're not that old, but it looks as though he used a cheap dodgy chain because the difference in tension around its length is massive.)

  2. I think you may have put your finger on it right there.

    A tight spot in the chain will be felt on every revolution of the chain (which is slower than the rear sprok and much slower than the front one) which gels with the low frequency vibration you describe.

    I probably wouldn't go chasing anything else until chain and sprox have been replaced with decent quality items.

    Beware of oval or eccentric cheapo aftermarket sprockets. Quality brand names should be OK however.
  3. Thanks for that - it does make a lot of sense.

    Frustrating if it's the case, since the sprockets still look decent, but should probably be replaced when the chain is... Ah well, will do it right this time and it should serve me well for the future. No idea why you'd put a crap chain on a torque-monster like the Bandit.
  4. You've got it in one. Irregular vibrations through the footpegs are usually indicative of a rooted chain.

    On the positive side, just wait til you get the new chain and sprockets on. The bike will feel like a million dollars. It'll be smoother, throttle response will feel more immediate, gear changes will be slicker and tighter... I love putting new chains on bikes, it's like getting a new bike.
  5. Cool beans - an extra 400 bucks or so has been kicked into the fund for the service: which might put it up near $1200 total with a full service and tune, but it'll still be worth it to have the daily use machine purring.

    OK, two more questions:

    1. Given that I'm doing the sprockets anyway, I'm not going to shag anything any more by riding it around for the next couple of weeks, yes/no?

    2. It's relatively unlikely to suddenly jam and lock up the back wheel in the middle of a corner or something, yes/no? i.e. it's only annoying to ride, not dangerous...

    3. (tricked ya!) Features of a good quality chain? O-ring, Q-ring, X-wing... ;)
  6. Yes no worries

    Yes no worries

    X-rings are good, as is tensile strength. DID make a good chain, as do RK.
  7. Awesome, thanx - one of many reasons Netrider is Number 3 in the country with a bullet.
  8. Had this exact problem before Bravus on old Bandit when some beutch :furious: ran into me side on. Managed to stay upright but she pushed the chain gaurd into the tyre and I ground to a halt from 50kmh. I pushed insurance for new chain and sprockets as she clipped rear end but they where having none of it, coz we put a dial indicator on rear sprocket and it ran true and chain looked fine. So after they made few cosmetics look pretty and straightened rear subframe-4 FARGIN months later, I got my bike back.

    Took it for spin and got 50 meters and could feel this ever so slight but obvious vibration and wobble :soapbox: FARG I was pissed off, after basically missing all summers riding. Anyways they replaced chain and sprockets and \:D/ perfect :grin:

    Oh btw, 1200 bananas for a major :shock: , change you oil, follow this http://www.billsbikesnservice.com/cam.htm
    and pay 100 bananas for carby balance, same deal. Either that or ride to Melbourne and I will do it for 1k :LOL:
  9. Well, they said 6-800 for the major, depending on what needs to be done, but that's a heavy duty major including a tune etc. Then I added in 400 for chain and sprockets, so it's not as bad as it sounds and I may well get out of it for a grand anyway, it just depends on whether there's much else in need of doing. Better to over-budget than under, though.

    Very nice to hear that all that nastiness will go away in a week or two.