Oscillating Scraping Noise Coming From Front Pulley Area

Discussion in 'Thunderbird' started by Ashlander, Mar 28, 2021.

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  1. Ashlander

    Ashlander New Member

    Jun 27, 2020
    8
    3
    St Paul, MN
    I got a 2010 Thunderbird with the 1700 with an issue I haven't been able to figure out. It has an oscillating noise, or like a "wub wub wub" sound when moving, it does it at all speeds but less noticeable at higher speeds since it occurs at a higher frequency then and there is alot of other noise to drown it out. The sound and frequency is entirely based on road speed, so braking, throttle, clutch, load, etc has no effect on it. I originally could've swore it was coming from the back so I thought it was a wheel bearing, but after replacing them it still occurs. I've noticed now, after getting it back out, that I can actually feel it (as a slight vibration when the sound occurs) in the foot pegs as it oscillates.

    My buddies and I had it on jacks last fall and ran the bike at about 30mph to try to locate the sound, and it seems to be coming from the center of the bike, around the front pulley area (this also rules out anything with the front wheel since it wasn't moving). Any thoughts on what the issue might be?

    Here's a video of the sound, nevermind the flailing camera. It also seems to be more prominent on the right side (but not by much), but I obviously needed that hand for the throttle.

     
  2. Helmut Visor

    Helmut Visor Only dead fish go with the flow
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    Oct 3, 2018
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    Hi Ashlander, that doesn't sound great. My mechanical skills aren't great so I wouldn't like to guess too much but possibly the front pulley of your belt drive isn't running true. If you get no answers in this section consider putting the thread in the Technical Section as that is where a lot of the knowledge hangs out. Good luck ;)
     
  3. Ashlander

    Ashlander New Member

    Jun 27, 2020
    8
    3
    St Paul, MN
    I just took the cover off to watch it while I rode around the block, and it didn't appear to have any play or anything.

    Could this be something with the clutch? How do they sound when they're going out?
     
  4. Pegscraper

    Pegscraper First Class Member
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    Jun 12, 2020
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    I'd say that's noise from the belt itself as it doesn't sound metallic. How old is the belt and how much is a replacement? I've no idea what the service life of the belt is but it might be worth just fitting a new one.
     
  5. Ashlander

    Ashlander New Member

    Jun 27, 2020
    8
    3
    St Paul, MN
    I haven't looked into replacing the belt yet. Not ruling it out just yet, but I can't think of anything that'd cause the belt to sound like that.

    The engine was rebuilt at the dealer about 5k miles ago, so I'd be surprised if it needed replacing. Could be rubbing on something, but it looks like it's clearing all the guards just fine. I might try removing them all and see if it still occurs just incase.
     
  6. TEZ 217

    TEZ 217 Crème de la Crème

    Mar 6, 2016
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    Carefully check the drive belt for any damage if some debris such as small gravel gets on to drive belt teeth it can be driving into the belt itself causing noise like this. look at pic below.
    DSC_0286.jpg
     
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  7. Ashlander

    Ashlander New Member

    Jun 27, 2020
    8
    3
    St Paul, MN
    I actually figured it out. It's definitely the front pulley bearing. I stripped the front pulley down to the bearing to get a look at it, and it's pretty bad. The cage basically just fell out, and at least one of the balls is broken/worn in half (7-o'clock position in pic 2). Crap load of metal shavings in the outer seal too. Gunna replace the bearing, change the oil, and give it another oil change after another 100-200 miles to hopefully get any remaining metal out.

    [​IMG] [​IMG] [​IMG]

    I just ordered one of these sets to extract the bearing without having to remove the engine and split the crankcase to get the shaft out and pull it, like the service manual expects you to.
     
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  8. Ducatitotriumph

    Ducatitotriumph Crème de la Crème
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    Apr 25, 2019
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    Well found and good luck sir!
    I'd also pull it out when the bike is on the sidestand as a small bit of gravity will help too to stop bits falling inside.
    Magnet too to help with shards?
     
  9. Pegscraper

    Pegscraper First Class Member
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    Jun 12, 2020
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    Wow, that is a seriously knackered bearing, good find! When it's out I'd be inclined to drop the sump and check for/clean out any fragments. It's a bit more work but still nothing compared to splitting the engine cases.
     
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  10. Ashlander

    Ashlander New Member

    Jun 27, 2020
    8
    3
    St Paul, MN
    I haven't looked around the engine too much on this yet, would dropping the sump be doable on the frame? If so, I'll definitely do that. I was going change the oil after anyway, and tear into the filter to check for metal.
     
  11. SuperHans

    SuperHans Senior Member

    Mar 11, 2020
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  12. Pegscraper

    Pegscraper First Class Member
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    I'm not that familiar with your bike so I can't say for definate if the sump will come off with the engine in situ. I've done this on a couple of bikes in the past but not a Triumph. Having to remove the engine will obviously means a whole lot more work. A magnetic sump plug, as suggested, is a good buy even if you don't have engine problems.
     
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  13. TEZ 217

    TEZ 217 Crème de la Crème

    Mar 6, 2016
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    Wow that's well fecked and your noise for sure, as said oil and filter change maybe consider a quick oil flush.
     
  14. Alatamoc

    Alatamoc Senior Member

    Mar 29, 2019
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    Uk
    The sump will come off with the engine in situ...but the sump gasket is complicated by having a coolant pipe in the way. But it's doable.
    I thought I'd seen most Thunderbird problems but this is a new one to me!
     
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