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Throttle lag??

Discussion in 'Technical and Troubleshooting Torque' started by deXtrous, Aug 7, 2011.

  1. Hey folks, so I've recently just discovered after riding a few other peoples bikes that my very own ZZR 250 has some sort of throttle lag (I think).

    What happens is, I'll be in first at the lights or something and go to take off, I twist the throttle a bit and it's sluggish at the start then after a second or two will seem to kick up a notch, without altering the throttle.

    Any possible reason for this? The bike is getting on with 70,000km's, maybe its the gearbox? Carby's been cleaned recently.
  2. It doesn't sound mechanical, more like carburetor tuning, Pilot screw setting perhaps, this affects power delivery from idle up to about 25% throttle.


    Motorcycle Carburetor Theory
  3. Pull a couple of spark plugs and see what they tell you.
    Running 95ulp
    Grey..... Way too lean and soon to blow.
    Brown. Tan colour perfect, and you troubles are not carby per say.
    Black. Sooty black = too rich. Wet black means it probably wont start again.
  4. Umm not meaning to sound too stupid but are you opening full throttle at 3kRPM and then when it hits the magic 5k it suddenly feels like it has more power? If that's the case then it's just the powerbands working for you.

    Just trying to rule out the simple stuff.
    • Like Like x 1
  5. Good point cardboardtenant, we have a tendency to jump for the complex first :)

    To the OP, wrap the throttle on harder and does it still happen?
  6. If he is comparing with other bikes and riding both in the same way i suspect a problem with his bike. Like CFVFR I suspect tuning and am thinking it sounds rich.

    But plug inspection should confirm.
  7. You say 'Carby's been cleaned recently.' Is there just one? Was just one cleaned? Who cleaned it? Pls forgive my gentle scepticism, but was it running better before that?
  8. Could just be you are riding a 250cc CV carbied bike. You are opening the throttle in the hope of getting more power, but the CV slides give you the power when it is possible.

    It could be a bottom end richness. The way to get this right is:

    Clean carbies
    set float height
    Adjust idle jet and throttle stop.

    Idle jet should be between 1 and 4 turns out. If it falls outside this range then you need a different size idle jet.

    But I'm just guessing it's the way you bike is.
  9. TPS maybe?
  10. The TPS IS the carbs.

    I'll second the suggestion that it could be just the learner friendly throttle response. Worth checking the mix and such though.