Two Seconds To Return To Idle

Discussion in 'Bonneville' started by bruno_c, Dec 1, 2022.

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  1. bruno_c

    bruno_c New Member

    Oct 19, 2018
    16
    3
    France
    On my 2017 bonneville T100 LC, after blipping the throttle, it takes around two secs to return to idle. Do they all do that or is it a problem on mine.
    Thanks in advance.
     
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  2. MICK LEONARD

    MICK LEONARD Well-Known Member

    Oct 31, 2022
    57
    68
    SOUTH COAST UK
    Sounds like a sticky throttle cable mate.
     
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  3. Carbtec

    Carbtec New Member

    Oct 16, 2021
    1
    3
    Nottingham
    Could be a sign they're running lean.
     
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  4. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    47
    28
    Cheshire UK
    They dont have a cable.

    I have a 2020....what LC stand for....

    When you say takes 2 seconds.....does that mean its holding a steady rev before they start to drop down to idle speed.
     
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  5. Jadorff

    Jadorff Noble Member

    Apr 14, 2019
    877
    443
    Adelaide Australia
    Thats fly by wire could be the throtle sensor depends on does it hold revs for 2 minutes then drops or as said above or does it take 2 minutes to slowly drop revs
     
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  6. beerkat

    beerkat Senior Member

    Aug 14, 2019
    850
    243
    Cheshire UK
    LC stands for Liquid Cooled.

    I have a 2017 Street Twin which obviously has the same engine as your T100. There is no rev counter so I cannot say for certain but there has always been the feeling that the revs are hanging for a moment after I close the throttle. Doesn't feel like 2 seconds though.
    This is in comparison with my two Hondas with carbs. The revs drop instantly when I close the throttle. In fact in many ways the carb system is better. I know the advantages of FI, but I get a much sharper response from the well set-up Hondas. But I guess you get used to (just about) anything, if I didn't have the carbed bikes I probably wouldn't notice.
     
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  7. bruno_c

    bruno_c New Member

    Oct 19, 2018
    16
    3
    France
     
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  8. bruno_c

    bruno_c New Member

    Oct 19, 2018
    16
    3
    France
    Thank you for all the answers.
    Being a 2017 model, it is not a matter of sticky cable. In fact the revs start to drop as soon as I release the throttle but slowly. Maybe it does not take 2 secs but it ils not as fast as on my 2001 Bonnie or other bikes I used to ride.
     
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  9. Jadorff

    Jadorff Noble Member

    Apr 14, 2019
    877
    443
    Adelaide Australia
    If the revs arent hanging on its as above both my honda and triumph are efi they drop fairley quickly I have cables but my car has no cables it drops a bit slower
     
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  10. Pegscraper

    Pegscraper Elite Member

    Jun 12, 2020
    3,053
    800
    Yorkshire
    I have to say, the fuelling on my Street Scrambler (same engine) is nigh on perfect even though it's a 2022 Euro5 spec version which means it runs very lean. Even though the throttle response is good the engine does not spin back to idle as quick as the 570cc single on my dirt bike. A requirement of the Euro5 spec is that fuel is shut off completely on a closed throttle until the engine is back to idle so the slower throttle back response must be purely down to the weight of the reciprocating parts. The difference is the dirt bike engine is a comparatively high revving, over square race bred motor with a lighter crank requiring a higher idle speed to prevent stalling compared to the lightly tuned, lazy road going motor in the Triumph. Even the 1400cc, 4 pot motor in the ZZR revs down quicker than the Triumph!
     
  11. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    47
    28
    Cheshire UK
     
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  12. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    47
    28
    Cheshire UK
    #12 nickjaxe, Dec 5, 2022
    Last edited: Dec 5, 2022
    Would need to test run my engine tomorrow....but I suspect its normal....lots of heavy stuff spinning....will take a bit for it to slow.

    I will fire mine up tomorrow and report back.

    In fact I have a vid I shot last week....will look at that now.
     
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  13. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    47
    28
    Cheshire UK
    #13 nickjaxe, Dec 5, 2022
    Last edited: Dec 5, 2022
    .
     
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  14. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    47
    28
    Cheshire UK
    Ok vid of my engine running....how does it compare going back to idle speed.

     
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  15. bruno_c

    bruno_c New Member

    Oct 19, 2018
    16
    3
    France
    Thank you for the video.
    I think on your bike the return to idle is quicker than on mine.
    I will talk to the dealer. Maybe a matter of remapping.
     
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  16. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    47
    28
    Cheshire UK
    Let us know how you go on....my bike has no cat so that could effect it....the cause a bit of resistance to exhaust flow....so could slow down the slowing.
     
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  17. Pegscraper

    Pegscraper Elite Member

    Jun 12, 2020
    3,053
    800
    Yorkshire
    I doubt a cat would effect the rev down as there's minimal gas flow with a closed throttle.
     
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  18. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    47
    28
    Cheshire UK
    Still sucks in air....has to blow it out again.
     
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  19. Pegscraper

    Pegscraper Elite Member

    Jun 12, 2020
    3,053
    800
    Yorkshire
    With a closed throttle, the (petrol) engine sucks in very little air, hence the vacuum in the inlet tract/manifold on overun, unlike a diesel where the air isn't throttled and is fully open to atmospheric pressure.
     
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  20. Baza

    Baza Elite Member

    Jul 25, 2020
    2,712
    750
    Home of Amazing Grace
    Seconds not minutes
     
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