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knocking noise on a zzr250

Discussion in 'Technical and Troubleshooting Torque' started by MrWasabi, Nov 19, 2007.

  1. Got my bike today, 96 Kawasaki ZZR250, and it was not starting...
    Fixed the issued, got it started, it was a short in one of the relays...

    Now that I can hear the engine running, I think I can hear a very slight knocking noise while idling. I have never heard a ZZR250 rev before and I dont know much about bikes but the only other thing i had to compare it to was an 85 model GSX250 and that engine sounded smooth.

    I open the throtle a bit on the ZZR to increase the revs slightly and the knocking gets faster. At around 3K it stops knocking all together and sounds normal.

    When the revs drop, they will drop below normal idle for a breif second and the knocking becomes a bit more obvious and you can feel it through the handle bars.

    Does anyone have any idea what it could be?
  2. I have found these motors difficult to get to idle smoothly, they do not fuel well at low rpm <3000rpm. But it is mostly likely the carbs out of sync. Imagine the cheapest solution first, then imagine the worst.
  3. how many km have your bike? ...maybe it's the camshaft chain.....or the chain tensioner.... :?
  4. Depending what sort of knocking noise you are hearing..... all ZZR/GPX's have a deep knocking noise at idle from the drive damper in the clutch basket, this noise gets louder with age and if the engine is out of tune. It is not a problem if the noise is this but still it's not comforting to have to listen to it just the same.

    Get your local mechanic to have a quick listen, I'd bet it is the clutch drive damper.
  5. It has about mid 25,000 Ks on the clock. It is a learner bike which has been passed along a group of friends. From what i could gather, some where along its life it has been mistreated, throtle opened right up and clutch popped to do a wheelie...dropped on its side, at low speeds etc...

    On a scale of 1 - 10, 10 being very difficult take it to a mechanic...
    How hard is it to inspect and/or fix the camshaft chain or chain tensioner?
    Also how do i go about tuning a bike? i know how to do it on cars, i have my timing gun and all and i am mechanically competent but i wouldnt have a clue where to start with a bike.
  6. If the knocking gets less when you pull the clutch in and pop it into gear then don't worry about it, it's normal for those engines. Just about every learner who gets one worries about the noise they make

    At 25,000km the cam chain isn't likely to be a problem yet. Electronic ignition so you don't have to worry about timing. Oil changes are easy so you can do that yourself. Carb balancing needs some gauges, so you might be better off getting a mechanic to do that.

    The main thing is stop worrying about it and just get out and ride it :cool:
  7. Cool, as soon as i get my license i will take it to a mechanic and get them to service it and see what happens from there...
    i did take a video of the engine running if anyone wants to hear it, however i dont know where i can host a video file so i can share it. I tried youtube but i have problems signing up to that... invalid parameters :/
  8. These engines are pretty robust and it's true they do knock at idle and I suspect all the way through the range but you cant hear it up high over the other noises :LOL:
    A carb balance will quieten things down heaps if they are out.

    Dont sweat to much as you'll probably be told its normal.