Sprint Lumpy At Low Revs

Discussion in 'Newbies Hangout' started by Dave Kimber, Feb 25, 2019.

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  1. Vulpes

    Vulpes Confused Member

    Mar 14, 2018
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    Hi and welcome.
     
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  2. Dave Kimber

    Dave Kimber Member

    Feb 25, 2019
    30
    13
    Bridgwater Somerset
    One photo

    AD2DFBC7-5135-4CA2-8D41-54C0E8E42850.jpeg
     
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  3. Wessa

    Wessa Cruising

    Apr 27, 2016
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    Very nice......
     
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  4. Dave Kimber

    Dave Kimber Member

    Feb 25, 2019
    30
    13
    Bridgwater Somerset
    Ok so I took the tank off removed the hoses one at a time and made sure they where correct as per Haynes manual.

    I did the let it idle without touching throttle for 10 minutes trick as I’ve been told this will reset TPS
    Had a good look at everything and all seems right no obvious air leaks.

    Took her down the road nothing has changed the only thing I’ve noticed is there seems to be a whine or whistle over the top of the exhaust note
     
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  5. David Cooper

    David Cooper Triumph Rocketeer.
    Subscriber

    Hello and welcome to the forum Dave.

    15e3a85db23c7072eaaba533acb6a97b.gif
     
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  6. Sprinter

    Sprinter Kinigit

    Aug 17, 2014
    6,027
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    Vacuum leak in the throttle bodies? allowing air in and upsetting the fuel mixture like oldyam said
     
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  7. joe mc donald

    Subscriber

    Dec 26, 2014
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    Dave Kimber
    You may need to get a new set of throttle body to cylinder connecting rubbers see if that is the problem. Picture looks good so hope you get it sorted soon as its a nice machine and one of my favourite bikes of all time.
    Ride Safe
    Joe.
     
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  8. Sprinter

    Sprinter Kinigit

    Aug 17, 2014
    6,027
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    Spray brake cleaner at the throttle bodies while running. If the revs increase there is a leak.
     
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  9. Tiglet

    Tiglet Vintage Member

    Mar 28, 2016
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    Hello Dave and welcome to the forum :)
     
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  10. Callumity

    Callumity Elite Member

    Feb 25, 2017
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    Nr Biggar
    As others have suggested it sounds like an air leak on the inlet side that is much less apparent at wider throttle positions. You might also have a stepper motor going lazy that affects throttle position. Time to try TuneECU and check for error codes?
     
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  11. Rocker

    Rocker Elite Member

    May 1, 2016
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    Try an injector cleaner only about a tenner
     
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  12. Dave Kimber

    Dave Kimber Member

    Feb 25, 2019
    30
    13
    Bridgwater Somerset
    Ok so I had a closer look and found this little crack where the vacuum hoses join was not noticeable until I removed it and the rubber seal was removed
    Could it be something as small as this? All hoses are brand new and a very tight fit .

    2B5D203A-F44A-4D10-AA9B-B247141E1AC6.jpeg

    A8B4FBE7-AD89-44B7-A5B6-45A39C913C1D.jpeg
     
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  13. Oldyam

    Oldyam Grumpy Old Git

    May 14, 2017
    613
    500
    ireland
    #33 Oldyam, Feb 26, 2019
    Last edited: Feb 26, 2019
    Yes thats all it would take, if you have some silicone sealer or similar you could try covering it with that and see what difference it makes before you buy anything. If it seals up ok then its your choice to leave it or replace the faulty bit.

    Thats part of the idle control valve assembly
    and the parts listed here are subject to changes by VIN https://www.worldoftriumph.com/part.../triumphmc/modelid/16178/block/100066741-0-2/
     
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  14. Dave Kimber

    Dave Kimber Member

    Feb 25, 2019
    30
    13
    Bridgwater Somerset
    Hi Oldyam
    I used a bit of contact adhesive and some electrical tape to hold it in place
    Put her back together and all seems ok for now
    I’ll see how she rides for the rest of the week but will probably buy a new part
    Many thanks to everyone
    Hopefully a problem solved
     
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  15. Judd Dredd

    Judd Dredd Giver of Drugs, Vaccines and Hard Truths

    Jan 13, 2019
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    here and there
    Welcome to the triumph asylum, home of the motorcycling insane
     
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  16. Dave Kimber

    Dave Kimber Member

    Feb 25, 2019
    30
    13
    Bridgwater Somerset
    Update on this matter
    Bike has now covered 700 miles since the fix and is running very smooth with no issues at the moment
    A big thank you to everyone for their help and support
     
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  17. Rich Bryce

    Rich Bryce Dead Eye Dick

    Sep 18, 2015
    2,987
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    Bedford
    Welcome aboard Dave. Enjoy the ride now you've sorted the problem. If you do need to buy any new parts remember you get a 10% discount from us at Pure Triumph Woburn. I'll go to 15% on T numbers.
     
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  18. Cyril

    Cyril New Member

    Feb 12, 2020
    13
    3
    Miami, FL
    Low end in 1st/2nd (1-3K) doesn't have torque expected .. discovered hose from airbox to ecu disconnected so put that back in place (rubber couplings on both sides crumbly!) but symptoms continue (not sticking at 4-5k on way down anymore .. still kind of snatchy 1-3k). Tank has slight vacuum after running for a bit so suspect not taking in air as it should .. two nibs towards rear of tank (1 overflow, other breather?). Which is which. If one on right (looking forward) as I suspect can I just stick a wire up to clear? Doesn't tank cap have ventilation mechanism as well? Thanks, - solution posted here possibly similar? Thx,
     
  19. Cyril

    Cyril New Member

    Feb 12, 2020
    13
    3
    Miami, FL
    Hi. Pls. read below. What vacuum pipes are you referring to? Thx,
    **
    Low end in 1st/2nd (1-3K) doesn't have torque expected .. discovered hose from airbox to ecu disconnected so put that back in place (rubber couplings on both sides crumbly!) but symptoms continue (not sticking at 4-5k on way down anymore .. still kind of snatchy 1-3k). Tank has slight vacuum after running for a bit so suspect not taking in air as it should .. two nibs towards rear of tank (1 overflow, other breather?). Which is which. If one on right (looking forward) as I suspect can I just stick a wire up to clear? Doesn't tank cap have ventilation mechanism as well? Thanks,
     
  20. Don the Don

    Don the Don Bigger Than The Average Bear

    Nov 5, 2019
    2,947
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    Hi and welcome
     

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