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GSX 250 S Carb Issues

Discussion in 'Technical and Troubleshooting Torque' started by w00dsy, Jul 2, 2010.

  1. Hi Everyone, Have had this Gsx for around a month now and it has had carby issues from day one, Idle is erratic will idle up and down and eventually cut out after doing that for afew times.

    I have to use the hand throttle to keep it idling at lights and when we eventually take off it will bog down and eventually rev cleanly. Almost threw me off the first time lol.

    I have had the carbs apart today and cleaned them out, got a little bit of junk out of them, i checked and set the float levels to what it says in my Workshop manual for it and now the bike has a horrible miss under acceleration will eventually rev freely and take off again. I have had it apart twice and dont really feel like doing it again today!

    Some details on the bike.
    1983 Suzuki GSX250S
    Km are Unknown as it has a gs450S speedo on it
    The carbs are Mikuni BS30SS

    I rang the local Suzuki dealer for a price on carb kits and they tell me i cant buy a kit, i will have to come in and buy everything individually.

    Anyone have any ideas? I didn't play with any other carb settings apart from the floats.


  2. If everything is clean, the next most likely carb problem is a leak in one or both of the diaphragms. Quite likely on an older bike.

    Another possible issue is a leak in one or more of the inlet stubs between the carbs and the head. Again not unusual on and older bike. Traditional trick to check is to spray WD40 all over the stubs while the engine is running at a steady speed. If the revs change when the WD is applied, there's a leak.

    The above assumes that the carbs are somewhere near to balanced and fitted with the standard airbox and filter, which should be reasonably clean. I'm also assuming stock, or at least baffled exhaust. If it's got pod filters or open pipes, all bets are off as the jetting is probably halfway to Timbuctoo, based on my extensive and painful experience of pod filtered, open-piped early 80s bikes.
  3. Hi Pat, Thanks for the reply. The bike has the standard airbox etc and it has an aftermarket exhaust on it, original was 2 pipes it now has only 1 out the rh side. Anyone else do carb kits for them to your knowledge? I have been told Genuine only?
  4. Ok carbs were apart yesterday, looks like the diaphragm cylinder has been rubbing on the body of the carb from sliding up and down as it has large areas where paint is missing, its still smooth but this i say has been caused by the needle in the cylinder is being pulled to one side by the spring inside it? Both cylinders have similar marks and yes both needles are being pulled to one side on inspection.

    It is now flooding badly, i am in the middle of pricing up some parts for it as i have confirmed u cant buy a kit for them.