Bike doesnot feel snappy.



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Thread: Bike doesnot feel snappy.

  1. #1

    Bike doesnot feel snappy.

    When it is cool outside my bike feels very snappy and responsive when I twitch the throttle for some burst of instant torque.

    But when itís hot outside like yesterday, the initial throttle input doesnot feel AS snappy. It can still accelerate fast but I think it doesnít feel as alive because there isnít that instant kick of torque.

    I believe it has something to do with lean/rich condition but my question is, do all stock motorcycle in general perform differently when itís hot/cold outside to some extend ? Or should they perform exact same each time no matter the weather condition outside.

  2. #2
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    Re: Bike doesnot feel snappy.

    Quote Originally Posted by Ghostrider619 View Post
    When it is cool outside my bike feels very snappy and responsive when I twitch the throttle for some burst of instant torque.

    But when itís hot outside like yesterday, the initial throttle input doesnot feel AS snappy. It can still accelerate fast but I think it doesnít feel as alive because there isnít that instant kick of torque.

    I believe it has something to do with lean/rich condition but my question is, do all stock motorcycle in general perform differently when itís hot/cold outside to some extend ? Or should they perform exact same each time no matter the weather condition outside.
    what year and model bike?
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  3. #3

    Re: Bike doesnot feel snappy.

    "Waiter, get me some turtle soup and make it snappy."

    But seriously, if its an older air-cooled, carbureted bike TMDT- That Machine Does That.

  4. #4
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    Re: Bike doesnot feel snappy.

    All internal combustion engines make more power with a cooler, denser intake charge up to the point where it is so cold that the fuel can't evaporate (which is outside the functional operation region of motorcycle engines - not many people ride when it is -40 outside).

  5. #5

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    Re: Bike doesnot feel snappy.

    Brian has it right.

    I know on my old Honda 450, below freezing you could get it to lift the front wheel without using the clutch. In typical riding weather it barely unloaded the front suspension.

    The same effect should happen on high hp bikes, but it may be less noticeable as the increased hp may just lead to increased wheel spin.

  6. #6
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    Re: Bike doesnot feel snappy.

    As said.

    Cooler air is denser so more oxygen makes more power
    Warmer air less dense so less oxygen les power

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  7. #7

    Re: Bike doesnot feel snappy.

    Is your Z1000 stock or have you or a previous owner done any mods - e.g. muffler, air filter, re-program?

    FI bikes have a map that should accomodate climate change. Perhaps the air intake sensor is malfunctioning?

    HDs have an engine temp sensor and mine went bad causing driveability problems (thinks it’s low engine temp so adds more gas causing rich condition). Not sure about the electronics on Kawasakis - a model year would help.

  8. #8

    Re: Bike doesnot feel snappy.


  9. #9
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    Re: Bike doesnot feel snappy.

    Would be nice to know what bike it is & if it is FI. Modern engines have an ecu & different sensors to monitor conditions. Change in atmospheric pressure, temperature & other factors change how the engine behaves.

    I have a feeling your ecu is not programmed properly or your temperature sensor might be off.

  10. #10
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    Re: Bike doesnot feel snappy.

    No amount of ECU programming can compensate from a fixed volume of air (the intake charge) having less oxygen in it (due to lower air density due to higher air intake temperature) and thus having less energy content available.

    If the calibration is off, or if something is wrong (e.g. bad temp sensor), that's obviously not going to help, but the laws of physics can't be changed.

  11. #11
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    Re: Bike doesnot feel snappy.

    Quote Originally Posted by Brian P View Post
    No amount of ECU programming can compensate from a fixed volume of air (the intake charge) having less oxygen in it (due to lower air density due to higher air intake temperature) and thus having less energy content available.

    If the calibration is off, or if something is wrong (e.g. bad temp sensor), that's obviously not going to help, but the laws of physics can't be changed.
    What I'm getting at is the stoichiometric ratio changes as the engine is hot & cold. If they don't get that right then it would affect efficiency.

  12. #12

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    Re: Bike doesnot feel snappy.

    Quote Originally Posted by RockerGuy View Post
    What I'm getting at is the stoichiometric ratio changes as the engine is hot & cold. If they don't get that right then it would affect efficiency.
    Huh? By definition stoichiometric ratio can't change.

    Whether the fueling system (carb or FI) compensates appropriately for different air densities obviously matters (which I think is what you were getting at).

  13. #13
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    Re: Bike doesnot feel snappy.

    Quote Originally Posted by FLSTC View Post
    Is your Z1000 stock or have you or a previous owner done any mods - e.g. muffler, air filter, re-program?

    FI bikes have a map that should accomodate climate change. Perhaps the air intake sensor is malfunctioning?

    HDs have an engine temp sensor and mine went bad causing driveability problems (thinks itís low engine temp so adds more gas causing rich condition). Not sure about the electronics on Kawasakis - a model year would help.
    Despite the FI mappings, extreme temperatures can still have an effect on the performance. Even today, my ZX10R felt down compared to when I was riding it the other day when it was cooler, and it's quite obvious even on my FI motocross bikes when racing too.

    I guess it depends on the bike, but the FI systems are only capable of compensating so much (hence the reason why everyone opts for power commanders)
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  14. #14

    Re: Bike doesnot feel snappy.

    That reminds me, I need to order some race fuel

  15. #15
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    Re: Bike doesnot feel snappy.

    Quote Originally Posted by GreyGhost View Post
    Huh? By definition stoichiometric ratio can't change.

    Whether the fueling system (carb or FI) compensates appropriately for different air densities obviously matters (which I think is what you were getting at).
    In a carb bike, you have to manually choke the engine or else it would never idle when cold. Choking enrichen the mixture. A warm engine with start without chocking.

    Most fi bikes automatically enrichen the mixture by programming in the ecu. When it is warm it resumes to a normal map.
    Last edited by RockerGuy; 05-28-2018 at 06:01 PM.

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