weird throttle response

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by prince, Jul 4, 2014.

  1. prince

    prince Been here awhile

    Joined:
    Jun 11, 2007
    Oddometer:
    108
    Location:
    Los Angeles
    it seems that my engine isn't responding to my throttle right away around the 4500/5000 rpm, it's a bit "jerky".
    i tightened the chain and i do have a loose graphite ring around one pipe but i can't think that that could be the cause. my chain and sprockets have about 3500 miles on them so i don't know what it could be. The chain was an expensive one and its in good condition, i do have a G2 throttle.
    It is something i' ve noticed recently, in the last 1000 miles.
    Any ideas, suggestions?
    thanks in advance
    #1
  2. Racer111v

    Racer111v Long timer

    Joined:
    Aug 21, 2011
    Oddometer:
    1,414
    Location:
    Hudson, NH
    An exhaust leak can mess with the O2 readings at the sensors. I would fix that first.
    #2
  3. TheRog

    TheRog Dirtylittle funhaver

    Joined:
    Jun 12, 2014
    Oddometer:
    81
    Location:
    down and dirty sacramento
    I have a 07. 990 adv. and they seem to have the freaky deaky throttle response.
    The transition from off throttle decel to on throttle accel is a big jerky affair..
    Riding along at steady cruise throttle has a bad flat spot when you role it on to accel.
    It's not the chain. It's Ktm's inability to sort a proper fuel map for a bike that's 7 bloody years old. Disgraceful if you ask me.
    The dealers don't give a shit.
    About the only thing that's worked is a custom map from a pro tuner with a Dino and a exhaust sniffer.
    #3
  4. Zuber

    Zuber Zoob

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    Sep 28, 2004
    Oddometer:
    2,877
    Location:
    Main Street, Shedd, Oregon
    I would guess you need to check the TPS sensor or other adjustments, valve clearance, throttle body balance, etc.
    #4
  5. ADVill

    ADVill Been here awhile

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    Sep 9, 2013
    Oddometer:
    611
    Location:
    West Tn, USA
    I just adjusted the valves on my '08. I can't believe it made that much difference in how smooth the bikes is. I still think it's something else but I did nothing else.
    #5
  6. prince

    prince Been here awhile

    Joined:
    Jun 11, 2007
    Oddometer:
    108
    Location:
    Los Angeles
    the valves were adjusted 3000 miles ago, so i'll start with that ring and go from there. Also after i switched to FMF can i only did the 30 mns "running adjustment" on the bike, it hasn't been properly tuned with a map. I guess that will be my second thing to do ( not looking forward to it since there in an extensive thread on it which means its unresolved).
    #6
  7. Bighat

    Bighat Adventurer

    Joined:
    Nov 18, 2013
    Oddometer:
    70
    Location:
    Dallas
    Check with the dealer, there has been a map update but I'm not sure when it was issued....my 07 runs great all stock...
    #7
  8. crashmaster

    crashmaster ow, my balls!

    Joined:
    Mar 9, 2007
    Oddometer:
    5,558
    Location:
    Alaska
    Jerky throttle and a flat spot around 4500 rpm? My 07 has been that way for 70,000 miles.
    #8
  9. prince

    prince Been here awhile

    Joined:
    Jun 11, 2007
    Oddometer:
    108
    Location:
    Los Angeles
    ok so i took my bike to my mechanic, inside line moto in OC, he tries the bike and then the bike dies. It turns out it's a broken spring retainer.and it's a complete engine rebuilt. around $4200. i am at a loss here, my mechanic told me he never saw this before, does anyone? see attached photo of the culprit.

    Attached Files:

    #9
  10. Boatman

    Boatman Membership has it's privileges ;-)

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    Mar 9, 2005
    Oddometer:
    12,107
    Location:
    Petersburg, NY and Mill Spring, NC
    Why a complete rebuild? Did the valve drop on the piston? Not sure why that would require a complete rebuild. :dunno
    #10