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ZZR250 - Slow throttle response & trouble starting.

Discussion in 'Bling and Appearance' at netrider.net.au started by Linux_insidev2, Nov 30, 2007.

  1. Hey guys,

    Recently balanced the carbs, replaced float needles and adjusted pilot screws to match kawasaki specs.

    However since doing that, The bike has had poor throttle response and when starting the bike - if you don't hold the throttle high (to say 3,000RPM) the bike will die off, when it does I have a hard time starting it and have to pump the throttle while holding down the starter.

    Any ideas?

  2. sounds like the float level may be set too low... and as a result its running too lean


  3. How did you balance the carbs? What tool did you use?

    While you had the carbs apart did you remove the pilot jets and check that they were clear?

    It sounds like a blocked pilot jet, which could occur during the service if:

    1) There was dirt in the bottom of the float chamber already and/or

    2) Some dirt was added during the cleaning/service process, such as a bit of fluff from a rag...

    The pilot jets have a very small hole which is easily blocked.

    You replaced float needles - did you also check/measure the float levels?
    If the float needles were not identical or correct they could have changed the float level, making it lower.

    Did you replace the float seats as well? They need to be paired with new needles.


    Trevor G
  4. My question is why did you touch it in the first place? If there was something wrong to begin with it may give a clue to the correct reply...
  5. Oh okay,

    I did it because one of the float needles was worn, and the fuel tap has an issue - it's dripping when the bike is off and it's supposed to be vacuum operated.

    The engine was flooding, and one cylinder wasn't firing properly under 3k

    Carb sync was off, adjusted that with a set of vacuum gauges all with the assistance of my old man.

    Asked kawasaki for a needle seat, they said they don't do them for the GPX/ZZR's (the carbs are 2x Keihin CVKD 30's if that helps)
  6. i had very similar issues with my zzr the other day. then i just filled up with petrol. worked well :grin:

  7. So it ran properly at first, then? Otherwise you cannot sync the carbs...

    Then what needle and seat did you use? If it holds the floats at a lower level (further away from the mating surface), then fuel pressure would be less. Not quite enough to cause the symptoms you have given.

    I still go for blocked pilot jets thru the presence of rubbish in the tank/carbs.

    Unless it is actually running rich because someone left the pilot jets out after dismantling the carbs...does it start easily when cold?

    Hope you can solve it soon.

    Trevor G
  8. I had a poor throttle response after cleaning out my carbies recently, turned out to be that i'd crushed the right diaphram slightley when placing the caps back on, it was only small so a bit of sealant took care of it. :grin:

    Wouldn't really know how you could change the float levels without having done something drastic.