Thunderbird 900

Discussion in 'Technical Help' started by Graham MacKenzie, Nov 15, 2020.

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  1. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Can I get some advice please. I ride a Triumph Thunderbird 900, 1st registered 2001. 35,000 miles and regularly serviced.
    Lately, on the open road, the bike runs sweet as a nut, but at slow speed, in say 2nd / 3rd gear, the machine coughs, splitters and can die on me. It will restart no problem, but needs high revs to gain sufficient power to move off. If I start it from cold, it will tick over no problem.
    I have established that there is no water or muck in the tank, and it has fresh fuel.
    Any help or advice would be appreciated.
     
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  2. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Hi there Chiar1. Used two tanks with Silkolene Pro boost, which I thought would do the same job as Red ex. If you think Red ex will possibly help I'll try. Planning to remove and check fuel filters, but if that were the problem I'd have thought Tick over would be problematic.
     
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  3. Erling

    Erling Elite Member

    Dec 12, 2017
    1,123
    943
    Norway
    Hi Graham, could be a number of reasons, but my first suspect would be the idle jets. Are you using the choke when you start it successfully from cold,?
     
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  4. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Hi Erling. Yes, choke to start ,and it starts first time. Once engine warm, close off choke, and she ticks over fine for ages. Crack open the throttle, and she spits, farts and coughs until higher revs reached, then runs fine. Open roads from Spean Bridge to Eileen Donan on Sky road.....ran like a dream. Pulled into car park and engine died. Started first touch of the starter. coughed into main road, smooth as you like on open road.
     
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  5. Erling

    Erling Elite Member

    Dec 12, 2017
    1,123
    943
    Norway
    Your symptoms sounds familiar to what I once experienced: Stalled when idleing, ran fine on choke and when on main jets. The idle jets have very tiny holes which clog up easily, and after around 20 years perhaps they should just be replaced rather than cleaned. After you have it running fine, I recommend staying away from ethanol fuel if you let the bike sit for longer periods of time. Where I live I have to park mine for six months and I know from experience that ethanol means trouble if stored. Good luck with it, you have a great bike.
     
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  6. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Many thanks Erling. Studying Haynes manual as I write. I'll see about replacing the idle jets, and while I'm at it, is there anything else I should do when the carbs are laid bare.
     
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  7. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Hi Bikerman. yes, Air box replaced about 18 months ago. Very little mileage since then due to Covid and health problem last year.
    Thanks.... all advice / help appreciated.
     
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  8. Erling

    Erling Elite Member

    Dec 12, 2017
    1,123
    943
    Norway
    Were it me, I wouldn't touch very much if it works well as it is. Apart from the obvious stuff, like cleaning the bowls for possible debris. Replacing the rubber inlets is good advice.
     
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  9. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Many thanks to one and all. Got to say advice amazing. Unfortunately, it means a right load of work. Ah well, bike off road for winter; a winter project looms. Thunderbird and road salt don't mix very well. Cheers guys.
     
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  10. t552

    t552 Senior Member

    Nov 17, 2014
    415
    113
    Bristol UK
    Pilot jets.

    FB_IMG_1606229685853.jpg
     
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  11. t552

    t552 Senior Member

    Nov 17, 2014
    415
    113
    Bristol UK
    It was not my bike but a friend's son's bike. If mine the hands would be spotless lol.
    The fault was as described and one pilot was blocked. A poke with copper wire sorted it. It was a 95 low miles bike and the carbs had never been off.
    Correct it could be many things. But I think pilots in this case.
     
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  12. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Hi Bikerman. Advice please. At your suggestion I have ordered new , " idle jets " from Triumph , but the Parts Department identified them s as, " needle valves ", which are now bought, paid for, and winging their way to me. But, are idle jets and needle valves one and the same thing. Triumph implied that they, ( Triumph ), simple name them differently. Seems strange and I worry I'm getting the wrong part.
     
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  13. t552

    t552 Senior Member

    Nov 17, 2014
    415
    113
    Bristol UK
    Pilot jets is what you need.
     
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  14. capt

    capt Elite Member

    May 8, 2016
    3,052
    750
    western Australia
    Another possible area in this vein. That can cause running too lean the rubber manifold's between cylinder head and carburetors perish with age , they crack and leak ! Vacuum guage will confirm if faulty , visual check can also be a good start !
     
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  15. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Hi Bikerman. Thought you may be interested in this . It appears that " Triumph ". Don't stock / supply the Pilot jets for the KEIHIN carbs on my Thunderbird 900. Everything else is stocked, but not these. Obviously I'll use Mr Google to try and locate, but may be of interest to any members who enquire with the same problem.
     
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  16. t552

    t552 Senior Member

    Nov 17, 2014
    415
    113
    Bristol UK
    Allen's performance is the place for mikuni or keihin carb parts.
     
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  17. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Thanks for this. I'll contact them Monday.
     
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  18. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Ok guys.... Not out of the woods yet.
    As recommended , the Carbs have been removed and the float chambers found to be full of crud. Chambers cleaned out, all jets cleaned, tank cleaned out , and while tank was off plugs one and three removed cleaned and replaced. Everything put back together including new rubber seals all round, but problem at low revs remains. No.2 plug impossible to get at. If that plug was seriously fouled up or u/s, could that cause my stall / stuttering problem. Advice appreciated.
     
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  19. sprintdave

    sprintdave Nurse,he's out of bed again

    May 25, 2014
    1,491
    750
    Birmingham
    Well it sure wouldn't help.
    I think you need a thin walled box type spanner like the original Triumph one to get Centre plug out., it is a faff tho.
     
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  20. Graham MacKenzie

    Aug 22, 2015
    18
    8
    Lochaber
    Many thanks. Seems I'll have to source one. What a pain !!!
     
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