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low down engine rpm trouble on Bandit 1200

Discussion in 'Technical and Troubleshooting Torque' started by sylvan, Nov 12, 2007.

  1. G'Day All,

    I have been having some trouble with the revs on my 2001 1200 Bandit.
    At about 2000 rpm the bike idles between 1500 and 2000 rpm alternating for about a second each time. Most noticeable at start up.

    Local dealer / mechanic tuned the carbies at 40 000 major service and said that it is not uncommon in GSXR1100 engines (pretty much the same engine).

    I am just looking for some opinions on whether this is true or whether there may be a relatively easy solution.

    It really does not affect the ride at all (low revs) but I would hate for the problem to get worse or happen higher up.


  2. So idle is rough at startup? Yeah, it will be. Does it stabilize when warmed up?
  3. These engines should be smooth as......
    I suggest you look for a vacuum (sp) leak.
    If the exhaust and jetting is standard idle should be around 1200RPM 2k is way to high.

    What colour are the plugs and are they all the same colour?
  4. Its not a parallel twin :LOL:
  5. By 40,000kms the carbs may need looking at, the air cooled Bandit 1200's have a tendency due to the angled intakes and the vibrations to wear the needle/seats.
  6. ?????
    Try rewording your problem

    A few points on these engines:

    The idle for these should be about 1100.

    The carbies do need a bit of attention reasonably regularly. A clean and balance won't hurt.

    Needle jets do wear.

    Fuel and vacuum lines need to be good.

    Other then that, try rewording you question so we can attack the exact issue
  7. Bandit at low rpms

    The bike does idle fine at 1100-1200. The carbie has just been looked at and balanced. The valves were checked as well.
    If I am creeping along in traffic (Sydney) and have the engine at 2000 - 2200 the engine will then move between 1500 and 2200 without any adjustment of throttle. It makes for some jerkiness at low speed.

    I have not checked the plugs but at the last major service they were all fine.

    Cheers for any help,

  8. You sure that that isn't just a result of slipping the clutch in and out?
  9. yes I am sure.
  10. At 2000rpm you are very much still on the idle jet with these things. You may need to get the carbies cleaned, including pulling the idle jets and making sure they are clear. They are tiny on these things, so it doesn't take much gum to bugger things up.

    As mentioned, the needle jets may also be contributing. This is just wear and tear and they will eventually need to be replaced.

    But to be honest, it all sounds a bit like wear and tear to me and you shouldn't really be riding down that low, even on this engine.

    You may go to a lot of hassle and never get it to where it used to be.

    Select a gear lower for now if it's not too bad.
  11. seems like a vacuum problem to me. Incorrect seals in the vacuum system or broken vacuum components will cause the bike to vary in rpm at idle.
  12. Ive seen this problem on a few Bandits, as for a cure, unfortunately not real sure. My 99 model is fine, but if it sits awhile-i.e.winter, it tends to idle and do similar for a bit, week or so and a few rides, then sorts itself.

    I have definitely noticed what you descibe on 2001 onwards models, in at least 3 other 1200,s I looked at buying. My 06 model does the same from start up till well warm. Coughs and splutters and jerks till its at running temp, then its fine. I always try and let my bikes warm up on idle for a few minutes anyways, so hasnt been a huge issue.
    If you look at the intake manifolds on these at start up, they pulsate like a bullmouth frog, which I always thought could lead to crack the intake manifolds and allow air to be drown in, which would in turn explain some rough idling.

    Try asking Mick Hone workshop-03 9890 0304, they know there chit with these. I have asked them exact same question but I really cant remember the response :? but seem to recall it was along the lines of its a characteristic of some,and not really a firm answer unfortunately.
    Love to hear the fix if you find it :grin:
  13. Bandit revs

    Thank you everyone for your imput. The carbie was inspected and cleaned recently so I think it must be a characteristic of the bike. She is a great ride and this just adds to the character. Coming up to the summer months I assume the bike will improve. I let her warm up for about three minutes at the moment, will give her longer from now on.

    Bugger of a thing is that traffic means I am in first at those revs so can't go any lower. Will just have to rev her a bit and pull in the clutch.

    Thank you especially to Movin who has reassured me that it is nothing major.

    P.S I will get the jets and seals looked at next service.

    Ride safe and enjoy the good weather on the way!
  14. Re: Bandit revs

    Mate, excellent Bandit info here maximum-suzuki.com It still doesnt sound quite right to me. :?
  15. Re: Bandit revs

    Then, it may be one of two things that they neglected to do properly. They may not have set the float levels right. these carbies are sensitive to that.

    And/or the may not have re-synced the carbies afterwards.