Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

02 ZZR-250 suddenly says "She canna give nae more cap'n

Discussion in 'Technical and Troubleshooting Torque' started by bragi0, Sep 21, 2006.

  1. I was riding into work this morning when my bike started to misbehave. I was overtaking someone, doing about 11K RPM at 2/3 throttle when I suddenly had to back off then get back on the gas.

    Only there was no getting back on the gas. It's coughing and spluttering and generally not producing any power. It's ok up to about 1/2 throttle under 4.5K/5K RPM, but then it just coughs and splutters. It free revs OK (I don't do that beyond 9K RPM, but it was fine to there). Any throttle setting over 5K RPM induces coughs.

    Any ideas?
  2. My best guess is that as you increase the throttle is the carburettors start to use the main jet to provide fuel. A good clean/blow out of these jets (and the others while you're at it) and the fuel passages ways could see it right. Odd that it would happen mid-ride though I think.

    You might want to check the action of the throttle valve and throttle arm/lever as well, perhaps it could be stuck somehow.

    Is it any harder to start? Does it now idle rough? I believe a carburettor problem is the most obvious.

    Disclaimer: Not a mechanic.
  3. It starts and idles fine, it's not related to engine temp either.

    Now I have to figure out how to get to the carbies with my minimal toolkit :)
  4. Hopefully you'll be OK. On my bike the carbs (and everything that I need to remove to get to them) is all done by phillips head screws apart from a couple of bolts so it's real easy.

    My advice to you, take notes as you dissemble things and sort/label everything you take out. If you have a digital camera use it to take photos of how things were. Doubly important if you don't have a service manual for it.

    Once you have the carbs off the engine, drain the float bowls of fuel (I can't do it before I take the carbs off on mine, the ZZR might be different) using the drainage screws. Remove the float bowls, clean the inside of the float bowl with carby cleaner then unscrew the jets and give them and the passages a good blast through with more carby cleaner. Ideally follow it up with a blast of compressed air.

    Wear a mask and eye goggles as well, carby cleaner isn't the healthiest stuff and trying to put it through the jet passages using that little plastic tube under high pressure tends to squirt it off in unwanted directions.
  5. Re: 02 ZZR-250 suddenly says "She canna give nae more c

    She might have jumped a tooth on the cam :idea:
  6. If it's playing up under load, my guess would be spark.

    Pull your plugs and make sure you are getting good spark.

    I'd be doing this before I pulled carbies off.
  7. Is there a reason for this? I'm not questioning it, I'm just interested as to why a spark problem wouldn't show up at idle/low rpm as well?
  8. coils/plugs/leads could be breaking down as loads/heat increases, mechanicals/electricals are weird 'n wonderful things that come out with the strangest symptoms.

    My money is on the primary jet in the carby, heres how to suck it's guts out.

    You need to be able to completely cover the big hole in the middle of the carby so may need to remove the air box.

    Get as many revs as you can then cover the carbys air suply with your hand(if possible) while pumping the throtle hard and fast.

    Before the bike totaly floods itself and stalls, hand off the carby and keep it running, repeat as neccasary.

    What you are doing is sucking excess fuel through the jets and trieing to dislodge the blockage.

    Replace fuel filter if this is found to be the prob.
  9. Is it like the coughing and spluttering you get just before you run out of fuel?
  10. When you get a spark problem it usually first appears as a problem under load.

    At idle the conditions in the cylinder are much friendlier.

    fuel injection specialist make a lot of money cleaning and service injectors, because people are confident that is where the problem is. Usualy all they need is new plugs and leads.

    The other thing to check for is a vacuum leak. Check all your hoses and fuel lines.
  11. I found the exact same problem with my GPX 250 today. Was thinking it is the carbs and was goin to pull them apart on Monday and give them a clean. Let me know how you go. If you fix the problem b4 then and what it was.
  12. didn't I help u fix this????