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flat spot

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by pragnasty, May 19, 2005.

  1. im having problems with me whorenet
    im getting a flat spot through acceleration at about 10,000rpm and onwards. throttle runs on/off on/off very ragged accceleration.

    what would be the cause??
    ive drained the carbies (very slight particles)and checked for water in the fuel (NONE). running carbie cleaner at the moment. checked air filter ( i am due for a newb)

    any other thoughts on what it could be? :idea:


    cheers linz

  2. just a point note.... i commute daily sitting on about 120 kms for about an hour a day. (10,000rpm) would this mayhaps have contributed?
  3. How old are the spark plugs pragnasty?
    Try a new set in the hornet and see how that goes. Make sure they are gapped correctly.
  4. just put plugs in 1000km ago. i think it might be the carbies are blocked, mainly the main jet. through riding the bike today, she ooonly starves for fuel at full crank. bloody annoying.

    so now it takes me ages to get up to the speed limit. the mopeds pass me... :roll: :roll: :roll: :roll:
  5. What you describe is what happened when I filled my bike with Optimax, and sometimes with normal unleaded. The throttle response is very sluggish, and acceleration is ragged as if starving for fuel.

    I suggest running three or four fills of Mobil Synergy 8000 or BP Ultimate 98. You may be surprised as I was, especially with throttle response and acceleration, but it will take a few fills to clean out the old fuel from its system.
  6. I have put BP premium unleaded in my bike instead of Optimax and my bike absolutely runs like shite. BP have a high octane unleaded as well which I have not tried.

    After a few tanks of optimax, my bike runs very smoothly.

    But its not a 'flat spot'. The lousy running is right through the rev range.

    But it sure wouldn't hurt to try alternate fuels to find one that suits your bike.
  7. Blockage in the fuel line (fuel filter/ fuel tap/kink in fuel pipe)?
    Kaput fuel pump?
  8. Things that make the engine run too rich or too lean or run poorly at high rpm..

    * Dirty air filter - can make the mix too rich at high rpm
    * Faulty coil
    * Faulty spark plug leads
    * Faulty distributer lead
    * Check all electrical connections are secure and clean.

    Good luck.
  9. carbes could be out of balance too... check that... and also the pilot jets... check if they are set corect number of turns... some bike mechanics will set each pilot jet differently to make it look like they have done some tuning...