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Help Kawasaki ninja ZXR250c carb problem and vaccum valve

Discussion in 'Kawasaki 250cc In-line 4's' started by shahzeb, Mar 7, 2016.

  1. shahzeb

    shahzeb Member

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    I searched this forum and found that the A model cdi has a 6 point and 4 point connector with 4 active points on 6 point plug and 4 active points on 4 point plug. whereas the C model cdi has 5 active point on the 6 point connector and 4 active point on 4 point connector. But the C model shows only 3 active points on the 4 pin connector. Anyone would like to rectify me ???
    [​IMG]
     
  2. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

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    Shahzeb, The details/information you seek is in the Resources section of this website. You have to pay a small fee and then you'll have full access to many documents and manuals for your bike.

    http://2fiftycc.com/index.php?account/upgrades

    The attached image shows the Vacuum hosing on my bike. This is a C engine with A carbs. I'm using the vacuum created by cylinders 1 and 4 to open the fuel petcock. cylinders 2 & 3 have their vacuum tubes sealed off. The atmosphere vents on the front side of the carbs are open with no hosing. If you're wondering why you can see this hosing without a dirty great airbox in the way, it's because I have modified the standard airbox for easy removal and installation. The only hose going into the custom airbox is the crankcase breather hose.
     

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  3. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

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    Unfortunately, no-one has ever found a factory document that is definitive on the CDI plugs and the differences from one to the other. All I know is the C model has a sidestand switch which won't allow the bike to start of the sidestand is down and that the C headlights are always "On".
     
  4. shahzeb

    shahzeb Member

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    The resources section does have the original wiring diagram and manual for the A model ? Looks like i am going to upgrade :)
     
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  5. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

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    excellent
     
  6. GreyImport

    GreyImport Administrator Staff Member The Big Cheese Contributing Member

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  7. shahzeb

    shahzeb Member

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    hello guys,
    So i would like to update u guys on my progress and seek your advises.
    So i finally recevied my complete carb rebuilt kit from motorcyclespareswarehouse. I cleaned all the bodies of the carbs with compressed air, installed all new parts, (installed all news seals aswell), installed the carbs back on the bike, and synced them.
    The bike is running great now on all rpms and the acceleration is just sweet, no hesitation at any rpm, idles great, dosent shut down once warm. removed one spark plug to check the colour and it was the "sweet brown" colour.
    But the story dosent end here i am still facing some issues, which are:
    1.The bike starts cold with 1 long self without the choke but once it is warm it wont start without full choke. no matter how much i try it wont start warm without choke. Checked the pilot screws setting, first I set them on 2.5 turns, than 2.75, than 3 than 3.25 than 3.5, still no luck, so i returned to 3 turns because at 3 turns the throttle response was quite quick.
    2.At idle if i snap the throttle real quick there is some stuttering for a second but if i snap the throttle gradually and slowly it revs great.
    SO guys need your advises on whats wrong.
    Additional info:
    Since the A model engine dosent use a vacuum valve i have removed it and installed the breather Tee hose directly to the airbox.

    -Another thing to add which might help others is that I can assure everyone that the "C" model CDI works perfectly on the "A" model engine.

    P.S @Frankster sorry mate, I could not update to a premium member because paypal dosent operate in my country and the fee is only accepted via a paypal account, so i am helpless, otherwise i would have upgraded for sure.
     
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  8. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

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    No probs Shahzeb. One of the site administrators might be able to help you get to the RESOURCES section of this website. Good to hear your bike is running nicely. What happens to your throttle response if you start turning your air/fuel screw in? The manual recommends 2.5 turns +/- .25, so maybe start going back towards 2.0 and maybe check the carb balance again. Are you running a #35 or #38 pilot jet?
     
  9. shahzeb

    shahzeb Member

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    I'm using the #35 pilot jet. ok, so after turning the pilot screws in or out i need to rebalance the carbs ??? I havent tried 2 turns uptill now, started from 2.5 turns out and went to all different turns stated above, but the carbs were balanced at 2.75turns. didnt balance them again. Will try 2 turns to be sure. The bike's throttle is surely better at 3 turns than 2.5 turns. I need to clairfy one thing, the pilot in the zxr is a air screw or fuel screw ? if its a air screw than turning it inwards would make the bike richer right ? and the opposite would be true if its a fuel type pilot screw ?
    Since the bike needs a full choke to start when warm, does it indicate that the bike is lean ?
     
  10. Frankster

    Frankster See the World before you leave it Staff Member Premium Member Ride and Events Crew

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    All good questions. Normally, changing the air/fuel mixture shouldn't affect carb balance as carb balancing is only making sure the throttles are opening in sync. Since the ZXR has 4 carbs, it is very important that they are synced. When they out of sync all sorts of weird stuff can happen. I only suggested checking the carb sync again to see if they are still in sync or they have gone out of sync. If they've gone out of sync, then you may have a secondary issue. Air/fuel is at an individual carb level...e.g. not all four carbs will/might need to be exactly the same. Blair from Litetek discusses air/fuel tuning in one of his recent posts. It's a good read.

    My understanding is that the air/fuel screw can be for air or for fuel depending on where it is...fuel or air side. I'm not a mechanic, so don't want to give you too much "what I think" things to try. Might be best to wait for one of the mechanics on here to give you directions/ideas. Personally, If you're okay to wind on the throttle, then I'd leave it alone. I'm assuming once the engine has revved past 2-3,000rpm the throttle reacts fine and the bike returns to idle without any issue.
     

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