1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

900ss Keeps Stalling At Idle

Discussion in 'Supersport (1974-2007)' started by ck_uk, Oct 17, 2016.

  1. I've just read Stav's posting with interest. Just been out on mine, fuel light was on so first port of call was filling station. However, on the way (only a couple of miles) I could feel something wasn't right, becoming jerky as if fuel not getting through. Filled up and problems continued. Every time I hit some lights it died. Restarted ok each time but had to keep revving it. Went straight back home so I could scratch my head in away from the public eye. What's the first step in the fault finding process? Sound like fuelling or electrical? Haven't changed the plugs in a while so maybe worth checking those first. As usual I've jumped straight onto the forum in a knee-jerk reaction, apologies.
     
  2. as usual, could be several things but if bike has stood plus been subject to damp periodically then would probably start by draining float bowls and checking contents for 'debris' and water in particular.

    If it still revs cleanly at mid to high revs then it's an encouraging sign that it might be above or blocked idle circuit(s) rather than anything serious fuel-wise or electrical. Whipping out the plugs and examining will hopefully reveal more clues.
    Does fuel pump sound normal/same tone e.g. not erratic?
     
    #2 Chris, Oct 17, 2016
    Last edited: Oct 17, 2016
    • Like Like x 1
    • Agree Agree x 1
    • Thanks Thanks x 1
  3. Like wot Chris says.................Plugs first, then in this order:

    Choke mechanism sticking on; faulty tank breather valve; throttle stop/idle screw (they can come undone if the spring is weak); fuel pump running OK; fuel filter blocked; float bowls off and clean out; clean tiny filter in the fuel hose tee at the carbs; balance screw shifted for the same reason as the throttle stop screw.

    I don't think it is electrical.
     
    • Like Like x 1
    • Thanks Thanks x 1
  4. sounds a bit like water in the fuel system possibly
     
    • Agree Agree x 3
  5. The clue might be in the way it was really low before you refilled it. My guess is water or debris in the float bowls.
    Fuel floats on top of water in the tank and water can get in there due to condensation. Worst case scenario here is water at the bottom of the tank which has then caused corrosion and you've got both water and rust particles in you float bowls. Fingers crossed it's not that.
    It's unlikely though, as the classic symptom for debris is the bike will tick-over but it won't rev. This is because the main jets get blocked by the debris but the idle circuit still works.
     
  6. Process of elimination of all the advice given. For the cost of plugs I would change them as a matter of course first, post up pics of the plug colour, it might help a bit. You getting any smoke?
     
  7. Ok guys I know you've all been worried SICK about this issue.

    The problem was the spark plugs. Both carbon'd up and one was slightly oily. Cleaned em up and the bike started immediately and ran perfectly, apart from all the usual dry clutch clatter etc. Just funny how it started coincidentally when I was low on fuel and only then when I was a couple miles down the road. I think I'll replace with new plugs anyway as it's probably due.

    Thanks all
     
    • Like Like x 2
  8. Uprated coils cured all plug fouling issues with my SS.
    @Exige on here was selling them. Not sure of the current situation
     
  9. When I got my SS it had NGK plugs.........but I thought I would change them during the service I did on the bike not long after I got it while sorting out other issues.

    I fitted new Champion plugs and had to try two sets.......on both sets it ran like a dog.

    So I compared the sparks from the old NGK and the new Champions..........The Champions produced such a crappy, tiddly little spark; whereas the old NGKs still had a nice big fat spark.

    So in went new NGKs with an even bigger fat spark.

    I have always used NGKs in my bikes since acquring my Guzzi in the 80s.......They always seemed to be a lot better than any others.
     
    • Like Like x 1
    • Agree Agree x 1
    • Thanks Thanks x 1
  10. running bosch plugs in mine found them to be
    great compared to ngk R plugs

    recently had friend with a z750 with similar symptoms
    turned out to be plugs
     
  11. personally I would remove the tank ( no Biggy) and drain. As mentioned in other posts I had something similar and changed the plugs and brimmed the tank, all good but every now and then the problem would return. Turned out to be a large amount of water in the tank ( bike living outside and tucked cap seal) worth checking if for no other reason than the tank rotting...
     
  12. I had an hour on the superlight earlier today and it stalled many times over :mad:, how embarrassing as the first five odd rides have been spoton with no issues, so i then google it and this wonderful thread came up.:):upyeah:
     
  13. Going back to a bike with carburettors takes a bit of time to get used to
    I’ve been surprised as to how much choke it needs from cold.
    I found like you the engine would stall often when cold.
    It takes miles for the temperature gauge to climb to 100*c
    So now I start on full choke, no throttle bring the revs down / half choke, and set off, 1/4 choke, only closing the choke fully when on the open road.
    Has worked so far.
    I think mine could do with a small increase in revs at tick over, my next job.
     
    • Like Like x 3
    • Agree Agree x 1
  14. Similar to you with the above but choke goes in much earlier, What's yours ticking over on the needle number at.:thinkingface:
     
  15. 900 to 1000rpm when warm
    Feels a tad slow?
    What’s your running temperature when fully warm/hot ?
     
  16. When i place my hand on it...very hot indeed;), i don't have that extra temperature gauge on the 1994 model so who knows.:thinkingface:
     
    • Like Like x 1
  17. That’s strange I’m sure my previous ‘93 ss had one?
    So what does your dash look like then?
    Any photos?
    What tick over have you got when hot?
     
  18. The engine fluctuates between 1 / 1100 but i'll double check this number.Sorry this's the best i can do at such short notice.
    DSCN7736[1].JPG
     
  19. Hey there’s no rush!

    I’m busy fitting a kitchen :)
     
    • Like Like x 1
  20. I used to do the same
    They don’t like revs when cold start and will stall if you cut the idle too quickly
    My dizzy would warm up while I got myself kitted up :D
     
    • Like Like x 1
    • Funny Funny x 1
Do Not Sell My Personal Information