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ZZR-250 stagered idle and RMP problems

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by dalez, Jun 25, 2008.

  1. Hey guys,

    My ZZR250 has been reving really strangely when stationary. It wont stay idle normally and will go back and forth from 2000 to 4000, and is less responsive when using the throttle. When stationary, the revs will rise quickly to 4 or 5, and then fall really slowly back down to 2.

    Im not sure when it originated, but i think it was after i cleaned out the carbs the last time. I thought that the problem would be air coming into the carbs through a gap or hole in the hose. So i took off the fuel tank and tightened the bands around the carbs and pushed them closer. This looked as though it solved the problem for the first 5 minutes i turned on the bike. But the bike began to idle eratically again, so im not sure whether this is the problem. Any suggestions or causes of the problem would be greatly appreciated.

    Thanks very much

  2. Firstly, when you say you cleaned the carbs, does that mean you actually pulled them off and stipped them down or just cleaned the outside?

    If you have stipped the carby's down, and it didn't have this problem before, there is a good chance that you haven't put something back together correctly.

    My suggestion is to clean the carbys again, making sure the rubber inlet manifolds are not perished, and bolt it all back up again. Check your throttle cable to make sure it is not binding.

    Good luck
  3. Trapped throttle cable when you refitted the tank?

    Also check your choke cable if you have one.
  4. Sounds like the carbies are out of balance or a vacuum leak somewhere. Check all your hose again and make sure none have holes or cracks.

    Also try running the bike with the fuel cap open and see if it fixes it. Even though this usually is a symptom of fuel starvation after riding it could be affecting it differently.

    Just a few ideas for you.[/quote]
  5. Thanks for all your responses.

    Pink angel, when i cleaned the carbs out i pulled them out and stripped them down like you said. Im beginning to think that the problem is that the connections arn't tight and there is an ar leak somewhere.

    GPZ1135, i checked to see if the throttle cable is blocked but its not. The screw binding the pipes connecting the carbs was slightly obstructing the throttle from being fully engaged, but i've moved it out of the way now.

    I'm going to do a big service on it on saturday and see if i can find the source of the problem. But i think that a vacumm leak is the most likely problem. Thanks for all the suggestions.

    Cheers guys
  6. Did you remove the vacuum slide diaphragms or the covers from on top of them?

    All the best

    Trevor G
  7. Thats where my money will be. Just a matter of where?
  8. I've fixed the problem!!!

    I took out the carbies today to check to see where the problem was. It was infact an air leak coming from the hoses connecting either side of the carbs. A seal inside the carb was also loose so that might have also been a contributing factor.

    I resealed all the leaks and the bike is running better than ever.

    Thanks for all the help!!!!! :grin: