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GSXF750 Servicing Help (Bad Idle/Stalling)

Discussion in 'Maintenance and Servicing' started by Nicholai_Chev, Jul 15, 2015.

  1. G'day

    Winter has come, and so has a gremlin...
    Last week I finished a 3000km trip from QLD and within days has suddenly developed;
    - Refuses to idle and requires constant idle adjustment to keep it above 2k/rpm.
    - Stalls when below 2k, or slowing for the lights.
    - High fuel consumption 300km a tank down to 150.
    - Drained a couple of teaspoons of oil out from the airbox.
    - White condensation when started cold for a good minute.

    I've flushed the tank, drained the carb's and put threw a full tank of premium and carb-cleaner without any success. Before the trip I replaced the sparkplugs and changed the oil/filter.

    My suspicions is the airfilter could be blocked and running rich. Before pulling the bike to pieces I would appreciate your thoughts.


  2. Fouled plug, faulty coil/lead or both.

    If it was air filter restriction, it would have to be severe to not idle at all, and then as you try to rev, it would only run rough and piss unburnt fuel out the back.

    Check it is running on all 4 cyls, particularly at idle.
    • Agree Agree x 1
  3. WhIlst i agree that its probably not the air filter Its easy to do, and it willl need doing at some time. Always do the easy stuff first.
  4. Thanks, I'll take the plugs out tonight.
    Any ideas on the oil in the airbox?
  5. It appears the engine is running on all 4 cylinders at idle.
    I sprayed the exhaust headers with water and they all evaporated it near instantly.
  6. Has the bike been on its side?
  7. Nope, always been upright since I have owned it.
    Airbox was cleaned out 4000km ago, when the drain hose bung was pulled out a small amount of clean oil dripped out.
  8. Does it miss at idle? or it just won't run?
  9. normal blowby from crankcase.
  10. It will idle somewhat smoothly at 2000, however at 1000-1500 it will fluctuate roughly and will eventually get slower and slower then stall over the course of 20 seconds.
  11. Make sure the vacuum line is connected properly to the MAF sensor, or MAF sensor is plugged in properly. It probably on the right side of your throttle bodies (cylinder 4). There's a chanace you did'nt plug it in
  12. Don't have one of those...good ole carbs!
    Did get me thinking, does a vacuum leak sound possible?

    Plugs and leads look ok...well they spark when turned over and jiggled.
    Other thought is the choke isn't fully disengaging.
  13. friend had that with his SV650 powered Cagiva.. some bit of the choke seized in the carb
  14. IANAM but sounds similar to the what I experienced with a leaking manifold, spray some wd40 around the carb->engine fittings and see if the revs change at all