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2012 R6 - Low RPM stumble after crash

Discussion in 'Tech' started by cBJr, Jan 21, 2020.

  1. cBJr

    cBJr Well-Known Member

    Last year, I had a medium speed lowside where my bike tumbled a bit. The bike ran fine afterwards, with the exception of a very low RPM stumble. Basically, if I slowed down too much for a corner, or didn't downshift enough, when I went to get on the gas, it would hesitate for ~1 second, slowly build RPM, then accelerate normally once the RPM's raised a little. I rode it around the neighborhood a couple months ago and it was repeatable there as well.

    I'd like to start getting the bike back into good working shape. Where should I be looking to address this issue?
     
  2. DonTZ125

    DonTZ125 Purveyor of Neat Toys

    Take a look at your TPS and APS, see if one of them got nudged. Calibrate and adjust if necessary.
     
    cBJr likes this.
  3. Boman Forklift

    Boman Forklift Well-Known Member

    Actually not sure what controls them, so what @DonTZ125 said may already cover this, but I instantly thought of the velocity stacks that go up and down in the airbox. They are controlled by a servo with quite a few moving parts, possibly something is disconnected?

    I do remember you could hear them cycle when turning on the key.
     
    cBJr likes this.
  4. MELK-MAN

    MELK-MAN The Dude abides...

    if the v-stacks are unpluged or for some reason not operating, the bike will start, idle, and run up through midrange perfect. Even if in upward position. You will have dramatically lower power as you try to get higher in rpm range though.. so not likely the issue.
    Can check your TPS settings and sweep range (twisting throttle) by putting your gauge in diagnostic mode. manual will show how to do this, and give you acceptable ranges for readings that appear on the dash.
     
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  5. Boman Forklift

    Boman Forklift Well-Known Member

    Thanks for coming in with knowledge, as stacks were the first thing that I thought of.
     
    MELK-MAN likes this.
  6. cajun636

    cajun636 Honda Junkie.

    Yep stacks were what I thought. Also make sure the teeth are lined up on the gears in there. Mine were off before
     
    MELK-MAN likes this.
  7. MELK-MAN

    MELK-MAN The Dude abides...

    without a doubt.. the bike will run like it has half power with em not connected and working ! :)
    .. and will say, it's worth a look-see in the air box, who knows what issue is caused if they are misaligned.

    lots of stuff could have been jarred in a tumble. i'd be going over the bike top to bottom. Something like a temp sensor in the plastic ram air tube in front fairing could be broke (but that will throw a code), stator could be on way out (not making sufficient voltage at lower rpm, not really caused by crash, just coincidence)
     
    Last edited: Jan 22, 2020
    Boman Forklift and cBJr like this.
  8. RM Racing

    RM Racing Tool user

    Could be as simple as dirty plugs that took on some oil during the kinetic chaos.
     
    track wagon, cav115 and MELK-MAN like this.
  9. Banditracer

    Banditracer Dogs - because people suck

    Yeah, what Rick said, always start with the simple things. I've had several customers self diagnose stuff and spend hours and hundreds before they give in and bring it to me and it turns out it's just the battery for example.
     
  10. Schwiz

    Schwiz Well-Known Member

    This same thing happened to a racer friend. Ended up taking out the fuel pump, and saw that it had started to come apart. There are pieces of the pump that are held together by clips and those broke and separated the unit from the housing. Just throwing yet another thing to look at. :)
     
    RM Racing likes this.
  11. MELK-MAN

    MELK-MAN The Dude abides...

    for sure easy to check.. just swap out a buddies tank with known good pump. snap fuel line in place, ride in pits to see if has stumble..
     

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