Runs Smooth Only On Choke

Discussion in 'Technical Help' started by TraiaRider, Apr 18, 2025.

  1. TraiaRider

    TraiaRider New Member

    Aug 4, 2024
    1
    3
    Sweden
    Hi,

    I have a Triumph Bonneville 2001 with carburators.

    It runs smooth when the choke(enricher) is engaged but even after a long time, with a warm engine, when the choke is disengaged it runs jumpy. Dies a little bit when gas is applied but then like jump into action.

    When even gas is applied it jumps now and again.

    The bike has TOR exhaust and hiflo airfilter. Airbox baffle is in place but will soon come out.

    Any tips on things to check out?
     
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  2. Pegscraper

    Pegscraper Elite Member

    Jun 12, 2020
    3,425
    800
    Yorkshire
    I'm not familiar with that model but if it has CV carbs, check the diaphrams for splits or holes. Bike carbs are pretty simple things so I'd be tempted to take them off, clean the jets and check float heights etc.
     
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  3. Tim Gibbs

    Tim Gibbs Active Member

    Oct 27, 2023
    163
    33
    Sunny Devon
    Ultra sonic clean of the carbs is a start, my 2001 model had running issues, mainly because the wrong jets had been fitted, but if the bike has been parked up there might be deposits from the fuel blocking up the jets.
     
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  4. TraiaRider

    TraiaRider New Member

    Aug 4, 2024
    1
    3
    Sweden
    Thanks for replies.

    Yes it got CV-carbs.

    I'm gonna do the TTP 1.5 stage tuning so then I will change the main jet but maybe clean the other parts and check diaphragm.

    I think carburators are a little bit daunting but I guess I will have at it.

    I would like a good manual though, anyone have suggestions?

    Should I buy som gasket kit as well?

    Also I heard the needle could be worn and might need changing.
    what do you think?
     
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  5. TraiaRider

    TraiaRider New Member

    Aug 4, 2024
    1
    3
    Sweden
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  6. TraiaRider

    TraiaRider New Member

    Aug 4, 2024
    1
    3
    Sweden
    If I am not able to find a way to clean carburator with ultrasonic, is there another way?

    Soak in fluid?
    Carefully try to unstuck the canals with thin brass wire?
     
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  7. Tim Gibbs

    Tim Gibbs Active Member

    Oct 27, 2023
    163
    33
    Sunny Devon
    Some recommend soaking in Methyl Hydrate and blowing out with compressed air, or you can buy proprietary carb cleaner in aerosol cans.
     
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  8. 243jimb

    243jimb Member

    Nov 27, 2018
    9
    8
    Canada
    It is likely that your idle jet(s) are blocked. This is the smallest jet in the carb and blocks easily if the bike has been standing with fuel in the carbs. It is straightforward to drop the bowl, unscrew the jet and clean it.
     
  9. TraiaRider

    TraiaRider New Member

    Aug 4, 2024
    1
    3
    Sweden
    I bought a sonic cleaner. :)

    Is there a setting on the jets that I will have to take note of before dissasembly or is it when I put it together to screw it in as much as it goes?

    Is there seals between the carburator house and the bottom bowl?

    If not should I use any liquid sealant?

    Tanks :sun:
     
  10. 243jimb

    243jimb Member

    Nov 27, 2018
    9
    8
    Canada
    Start with the easiest remedy first. There are "rebuild kits" available that includes the O ring for the bowl and other seals. An ultrasonic cleaner may not be necessary if you just drop the bowl and remove the idle jet. It sits right by the main jet. They simply unscrew.
    If that doesn't work then a full carb clean might be in order.
    There are no settings that you will disturb doing the above. I replaced the JIS screws on my carbs with SS allen screws, much easier to deal with. Kits are available but not necessary, all you need are 3mm allen screws.
    Don't use sealant anywhere.
     
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