2016 - T120 Wobble At Speed

Discussion in 'Technical Help' started by Alectron, Jun 10, 2019.

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  1. Alectron

    Alectron Well-Known Member

    Apr 26, 2018
    80
    68
    Sunderland
    Wheel alignment, head bearings and tyres all good but now experiencing a quite alarming side to side wobble of the bike at high speed, not tank slapping or any noticable movement at the bars.
    Has anyone ever experienced this or similar please.
    Any suggestions will be appreciatedo_O
     
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  2. Dozers Dad

    Dozers Dad Bushmills Chief Quality Controller
    Subscriber

    If the current tyres are the originals? Try changing them to Avons.
    That might sound a bit drastic but the standard tyres seem to cause several handling issues.
     
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  3. Alectron

    Alectron Well-Known Member

    Apr 26, 2018
    80
    68
    Sunderland
    Thanks for that. I put Avon Storm's on last year and they're great!
     
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  4. Dozers Dad

    Dozers Dad Bushmills Chief Quality Controller
    Subscriber

    Cool, well it's unlikely to be the tyres then mate?
    Not sure what else to suggest apart from wheel bearings, misaligned chain or something is loose?
    I've heard of the brake discs warping very prematurely. If they are massively out of true? I guess they could be catching the pads enough at higher speeds to cause a wobble?
     
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  5. Tricky-Dicky

    Tricky-Dicky Senior Member

    Dec 12, 2016
    608
    243
    Norfolk UK
    Also check fork oil levels as uneven damping can cause some funny effects.
     
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  6. sprintdave

    sprintdave Nurse,he's out of bed again
    Subscriber

    May 25, 2014
    1,080
    250
    Birmingham
    Front wheel out of balance , wheel bearing going?
    How did you check wheel alignment, the marks on the swinging arm may not be correct, check using other means
     
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  7. Tiglet

    Tiglet Vintage Member
    Subscriber

    Mar 28, 2016
    2,454
    1,000
    Cheshire
    Have you lost a balance weight off the wheel
     
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  8. stevethegoolie

    stevethegoolie Elite Member

    Oct 16, 2014
    1,911
    800
    East Riding of Yorkshire
    Tyre pressures??
     
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  9. Alectron

    Alectron Well-Known Member

    Apr 26, 2018
    80
    68
    Sunderland
    Many thanks for all your comments.
    Fitted a new DID gold chain late last year and always measure wheel position before and after with a ruler.
    Front wheel bearings are good and tyre pressures spot on, that's why I'm puzzled by this. However, wheel balance weights?
    The bike runs perfectly until we go over normal UK limits! I could comfortably go well over 90 or so (on autobahns etc) without any problem.
    Now this alarming sideways wobble starts before these speeds are reached!
    Thanks again for your comments
    A
     
  10. capt

    capt Senior Member

    May 8, 2016
    1,281
    250
    western Australia
    How old/worn is your back tyre ? I've found some times the wear can cause the tyre to run up the camber of the road and slide back down again. Try putting a few pounds more air in the rear tyre , if this relieves the symptoms all good, if it continues then the front has worn unevenly , front will feel like a ripple strip, replacement only option
     
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  11. Ron Ashurst

    Ron Ashurst Non of your damned business
    Subscriber

    Oct 16, 2018
    3,825
    800
    the Pits of Hell
    I did a google search and this is some of the responses not already mentioned.

    1. Rider placement upon the bike. Distribution of weight centered more toward the rear of the bike causes the front end of the bike to loose stability at speed.
    2. Front end mechanical problems. Not very specific.
    3. Is the tire pressure set to the bike or tire manufacturers recommended pressure?
    4. Weight distribution, ie saddlebags.
    5. Windshields
    6. Loose spokes
    7. Head bearings

    Hope this helps
     
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  12. Callumity

    Callumity Elite Member

    Feb 25, 2017
    1,771
    750
    Nr Biggar
    I know people like their alignment pointers and swingarm markings but every chain driven bike that I have owned has been aligned with string along the wheels for a base setting. It resolves any misalignment in engine etc.

    You need to allow for differing tyre widths fore and aft. Fishing line!
     
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  13. Alectron

    Alectron Well-Known Member

    Apr 26, 2018
    80
    68
    Sunderland
    Sounds good Culamity, thanks for that.
     
  14. Alectron

    Alectron Well-Known Member

    Apr 26, 2018
    80
    68
    Sunderland
    Callumity!
     
  15. Alectron

    Alectron Well-Known Member

    Apr 26, 2018
    80
    68
    Sunderland
    Thanks Dozers Dad. As far as brake pads are concerned, have you noticed how the inner and outer (front) seem to ware away uneven. Inner one first which is in contact with the disc immediately, outer quite a lot less ware.
    Just thought you might have seen this?
    Think it's worth reversing them to even out!
    Thanks
     
  16. Alectron

    Alectron Well-Known Member

    Apr 26, 2018
    80
    68
    Sunderland
    Oops, wear not ware!
     
  17. Dozers Dad

    Dozers Dad Bushmills Chief Quality Controller
    Subscriber

    #17 Dozers Dad, Jun 12, 2019
    Last edited: Jun 12, 2019
    I guess the pads that are in direct contact with the pistons. Hit the disc momentarily before the pads on the other side of the disc.
    If that is causing one pad to wear noticeably quicker than the other? It might be worth you giving the calipers a clean & service.

    Try raising the front of the bike (block of wood & a jack across the frame rails) Put the bike on the centre stand & only jack the front enough to tilt the bike back so it rests the rear wheel on the floor.
    Then spin the front wheel to see if the brakes are binding or the discs are warped?
     
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