2004 T100 790cc Bonneville Noisy 3rd Gear

Discussion in 'Newbies Hangout' started by robwas, Feb 12, 2024.

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  1. robwas

    robwas New Member

    Feb 12, 2024
    2
    3
    Northern Ireland
    Hi
    Recently bought a 2004 790cc Bonneville, lovely bike, but just noticed a grumble in 3rd gear, all the rest are fine, should I be worrying about this
     
  2. Helmut Visor

    Helmut Visor Only dead fish go with the flow
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  3. Bikerman

    Bikerman I used to have 5500 posts.

    Oct 29, 2014
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    Greetings from Lincolnshire.
     
  4. Tim Gibbs

    Tim Gibbs Member

    Oct 27, 2023
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    Dorset
    Check that you have the right oil, should be 10W40 semi synthetic, I have found that Bonneville gears are a bit oil sensitive.
     
  5. robwas

    robwas New Member

    Feb 12, 2024
    2
    3
    Northern Ireland
    Thanks for that, just about to service the bike for the new years run, bought Castrol Power1 Racing 10W-40, so hopefully that will quiten it a bit, not that noisy anyway, just hope it doesn't get worse and need extensive (costly) work done to the gearbox.
     
  6. Wessa

    Wessa Cruising

    Apr 27, 2016
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    Hi and welcome….
     
  7. Glenn2926

    Glenn2926 Senior Member
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  8. speeder

    speeder Noble Member

    Jan 3, 2019
    406
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    Had a similar issue with a friends Africa twin, stripped the engine only to find 2nd gear was badly worn, it appeared not to have been hardened correctly on manufacture.
    Hopefully an oil change will cure yours. Carefully check the old oil for metal particles using a magnet,if any are found suspect the worst.
     
  9. robwas

    robwas New Member

    Feb 12, 2024
    2
    3
    Northern Ireland
    Thanks,I'll be sure to check for metal bits, hopefully I won't find any
     
  10. Iceman

    Iceman Crème de la Crème

    Apr 19, 2020
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    Hi Robwas and welcome to the forum, if an oil change doesn't cure it then yes you need to be concerned, especially as you say it is the 3rd gear, in top gear there is no real load on the gearbox bearing, that would be more of an issue, it is difficult to say definitely as you state a "grumble", from that I take it that it is a rumbling noise as opposed to a whine, however neither is good, a high pitch whine is an indication of a failure sooner rather than later, a heavier rumbling sound is indication that the bearing is subject to heavy wear, my experience is once you get such a noise from a gearbox bearing it is very rare it goes away, it is basically telling you "I am unwell and get me checked out before I get worse". If it was down to the oil, then other components would have reared up issues before the gearbox bearing.
     
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  11. robwas

    robwas New Member

    Feb 12, 2024
    2
    3
    Northern Ireland
    Hi Iceman
    Thanks for that, it's hard to fully describe the noise, I call it a grumble, but it's not that loud, I think it is more like a light grinding noise between the gear cogs of 3rd gear. It is all quite in every other gear, so I'm assuming (hoping) that it isn't a bearing noise,
     
  12. Boothman

    Boothman Senior Member

    Jul 26, 2023
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    Hi and welcome to the forum :cool:
     
  13. R_1000

    R_1000 Elite Member
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    Welcome buddy :)
     
  14. speeder

    speeder Noble Member

    Jan 3, 2019
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    Another useful tip is to cut open the old oil filter and check inside for metal swarf....messy but a good thing to check.
     
  15. speeder

    speeder Noble Member

    Jan 3, 2019
    406
    313
    dorset
    Yes, sounds like a gear problem to me, trouble is that both the meshing gears will probably be damaged.
    The other issue is gaining access to them involves a complete engine strip.
     
  16. Iceman

    Iceman Crème de la Crème

    Apr 19, 2020
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    Hi Robwas, what you describe may be at a worse case scenario the selector fork, that said what I would do first is drop the oil, and give it a close inspection visually and manually, by that I mean feel the oil through your fingers, this may sound strange but you can feel metal particles that are not always visible, if needs be pore the oil through a strainer (one like is used for sprinkling icing sugar on cakes) as the mesh is finer. Take off and inspect the oil filter for signs of metal particles, noting the colour if there is any metal particles present, there will be some miniscule amounts present and this is normal as the engine and gearbox internals run metal to metal. If there is no undue particles then a new oil filter and a quality semi synthetic oil change may well sort it out, the next bit may sound very obvious, but check the chain tension is correct, and use the right method if re adjusting, then check the gear linkages for excessive play, they soon wear if left unattended during servicing and maintenance, finally make sure the clutch has the correct amount of free play and again adjust as necessary. Hope this helps and keep the forum posted on your progress.
     
  17. robwas

    robwas New Member

    Feb 12, 2024
    2
    3
    Northern Ireland
    Will do, thanks for that
     
  18. robwas

    robwas New Member

    Feb 12, 2024
    2
    3
    Northern Ireland
    Changed the oil and filter, no filings on the magnetic drain plug, and no metal bits to be seen in the old oil. Went for a ride, but could hear nothing anyway as it was a windy day and there's a lot of wind noise with my helmut. Bikes going well, so I'll try to listen a bit more carefully on a calm day, if we ever get one again, and hopefully it doesn't become an issue.
     
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