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Carbie recondition.

Discussion in 'Technical and Troubleshooting Torque' started by duff_boy, May 12, 2008.

  1. Hey guys,
    I'm not happy with the way my bandit is currently running (and has been ever since i got it). Im confident its a fueling problem. I took it to a certain mechanic on at Slacks Creek and they were like yeah yeah we will do this and that and it will be running great. Anyway, i pick it up and all they've done is aparently balanced the carbies(pretty basic) and left some sctraches on my tank. :evil: Bike running no better. It gives me the shits because i love riding this bike, just the way its performing is very average.

    Basically its faults are:

    -Hard to start, i have to hold the throttle open while cranking it and also after ive started it for about 5 seconds to keep it going. Applying the choke doesn't help, infact it makes matters worse, engine doesnt start at all and if i open the choke once it does fire, it kills the engine.

    - Absolutely NO power <4000RPM makes the bike very hard to launch unless i slip the clutch and rev it up alot. Regularly seem to bog down if i don't give it heaps of beans. In neutral throttle response is doughy at best when you rev it up from idle.

    - If i'm just cruising along and I have the throttle only open lightly, between around 5-7500rpm it seems to cough and splutter and carry on.

    - It also seems to be lacking a little topend power. Gets moving when you hit about 8000, vvt kicks in at around 9700rpm and you get a good boost but power seems to fade off after about 12,500rpm. Redline is at around 15000rpm and from what ive read peak power should be around 14000-14500rpm.

    - Idle is rough, brap brap brap. Even when ive got the idle set quite high at 1750rpm.

    Okay, so i have a spare set of carbies lying around that came with the mountain of spares i received with the bike. So i figure, give these to a competent mechanic to be cleaned, adjusted, float heights & pilot screws set correctly etc. Basically just recondition them, then ill fit them up and balance them.

    That said, can anyone recommend me a decent mechanic/shop in Brisbane to do this for me? I don't mind spending the money, i just want to get it running nicely, considering ill be keeping the bike for a while yet to come, until i'm off restrictions( another 9 months).

    cheers for any help :grin:
  2. Perhaps the spare carby is spare for a reason? Might be nackered.

    How many kms on bike?

    When did you last check/change;
    -engine oil + filter
    -spark plugs
    -air filter

    You don't mention any of the above? These are cheap bits of maintenance that will make a difference or at least ensure a longer bike lifespan if checked regularly.
  3. firstly find out what the idle speed is supposed to be for your bike. Some of these small 4s idle at 2000 rpm, so that may be most of your problem there.

    Secondly it sounds like your idle mixture is too rich. Try winding your idle mixture screws in 1/2 turn and see what happens.

    After that I'm guessing the needle jets are worn.

    If the bike has an after-market exhaust it may well be it has never been jetted to suit. It may be running the wrong main jet, the wrong needle height , the wrong idle jet and the wrong idle mixture setting.

    Get the idle speed right if that doesn't work have a little play with the idle mixture, if that doesn't work, then take it to someone who knows.
  4. With workshops these days unless the service manual is on CD or online they will have nuff all ability to perform the correct procedures and settings.
    Find a mechanic who has done these models before to give it a once over and get a quote for the work needed.

    Sounds like it could be a combination of issues leading to these symptoms.
  5. Bike has a genuine 30,000kms(its aust delivered, not import) I have comprehensively serviced the bike since i got it around 4,000km ago. All listed above, and more, has been done.

    Carbies are spare because the bloke i bought the bike off smashed his first bandit(t-boned a car). I have near a complete bike in spares.
  6. Actually for the GJ77a peak power (40hp) is at 13,500. The 14,500 figure is for the earlier 45hp GJ74a.
    Oh and +1 to ibasts post, definitely sounds to be running rich.