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ZX2R Issues

Discussion in 'Technical and Troubleshooting Torque' started by Jez79, Mar 31, 2008.

  1. Hi All,

    Couple of questions re my ex GF's bike. Its a 1990 Zx2r (think its a 1990?) and has a couple of small issues:

    Choke: If turned on a little when bike is cold it revs its guts out around 6000-7000 rpm, if you try and back it off, engine just dies. Is there a way to adjust this or is it a carby problem?

    Clutch: Doesn't grab until lever is nearly all the way out. I have tried to adjust using adjustor screw but its already wound all the way out. Do the cables stretch? Is it worth getting a new cable or is it likely to be something internal?

    Exhaust: When not ridden for a while, the bike runs a little rough and blows a little white smoke which I'm assuming is from moisture collecting in the engine/exhaust as oily smoke is blue black or grey? I'm hoping its not a head gasket but wouldn't think so as I thought engines shudder pretty bad if this was the case.

    Anyhow, any help greatly appreciated, let me know if I haven't included enough info.

  2. $10 says that the throttle cables are incorrectly adjusted. (Either that, or the idle butterfly screw is in too far.)
    Screw the cable adjusters right in, at both ends (I.e. make the outer cables shorter), and then adjust from there (Should be getting quite a bit of freeplay in the throttle at this state. if it is still overrevving, then back the idle adjuster screw out.
    You should be able to move the steering from full lock to full lock without a change in the revs.

    The reason you need choke to start, is that you are leaning out the mixture with the carb butterflys being partially open. (In this case)
    Even for an I4 (which I'm assuming it is), 7 grand on choke is far too much. Gut instinct, a roof of 4000 is acceptable, but you don't want to be revving the shit out of it from word go.

    Cables do stretch. however, I'd be taking the cable off and inspecting the ends for any frays or damage - if a couple of wires have snapped, the cable stretched quite considerably. If you are getting clutch slip along with the late engagement, then the clutch plates are excessively worn and you're going to lose a few hours replacing them. Keep in mind road bikes seem to generally have late clutch engagement anyway.

    The engine runs rough as the carbs aren't adjusted correctly, and white "smoke" is the water in the exhaust gasses condensing in the cold pipes giving off visible vapour - just like cars starting their daily commute first thing in the morning.
    (And cold engines have bugger all power as it heats up to operational temperature)

    Hope this helps! :)
  3. Our ZZR has a very touchy choke at cold. Back it off to fast and it stalls but is fine after the warm up. Full choke is about 4000rpm and warm up without stalling can be achieved at 2500rpm.

    Clutches wear out and cables stretch. Take your pick.

    Running rough with white smoke could be plug fouling from leaking valve guide seals after shut down. This will also affect cold start and cold idle until the excess oil is burnt off. How do the plugs look?
  4. Screw the clutch one right in, then go down to the clutch on the right hand side of the bike, and screw that one out around the same amount you screwed the other in, if its also out of adjustment, replace the cable. You may have to take the fairings off to gain enough access, I have not worked on a ZX2R much.

    The choke can be part of a fast idle, my gpx can get to 7 grand if its warm and you put it on, not when cold. At a guess you should clean the carbie as the jets are probably a bit blocked with gunk, so it won't idle without the choke en richening the mixture.

    Is the 'smoke' whispy or more solid, does it fade quickly, on a hot day, or does it stay around. Does more smoke come out when you back off, or when you accelerate, or alternately not change and stay around the same?
  5. Choke:

    I had the same problem with my 250... instead of using the choke use the IDLE knob... but make sure u tune it back 2 around 1.5k RPM once its warmed up... this does the same job as the choke... i just found it better doing this rather than spending $40 on a new cable and $20 on installation... (rather spend on a slab :grin: )


    There is no "easy-fix" for this and it is a very important to get it fixed... you don't want the cable to tear while riding... However... if you unscrew both ends of the clutch cable you will b able 2 pull the cord out of its actual plastic casing. give it some WD-40 and some elbow grease to clean it as it may b just dirty.


    it costs roughly $45 for cable and either 30minz 2 install urself OR $35 for a mechanic to do it for you...

    hope that helps mate...