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Help, bike stalling

Discussion in 'Technical and Troubleshooting Torque' started by firefling, Jun 21, 2005.

  1. Last night, as I rode home in the dark and rain, no problems from city along the freeway to Clayton (30 mins), yet as I was about 5 minutes from home, the bike started sputtering and stalled a few times. Had to put the choke on to prevent it losing the revs. But it jerked me forward a few times when it lost power then went back to normal. Was scary as hell as it was slippery on the road with cars and all in front. There's still half a tank of petrol left. Check the oil gauge when I got home, it's running a bit low, but not dried.

    Can anybody advise me on what was wrong with my bike? Do you think it was just build up of crap in the carbies? (I was riding very cautiously, didn't rev the hell outta my bike). Or is it something else?
  2. I had this same problem. I had to ride with the choke fully open to not stall at lights. I would have to really twist the throttle to move at all, and every now and then there would be a kick from the bike as if the power was appearing for a second. It turned out to be the carbs. Mine needed to be cleaned and rebalanced.
  3. How long since the last service?

    Sounds like either a fuel delivery problem (choke shouldnt have helped that much), air flow problem (happened to me a couple of times, choke will help in this case) or a spark problem (choke will assist here as well). Do you have an in-line fuel filter? Have you checked the condition of your air filter? and your spark plugs?

    If the various filters and plugs are OK then you can start worrying about the carby.

    I am not a recognised mechanic, and therefore cannot be sued as one (hopefully)
  4. Does the SV have a carb?
  5. pre 2003 did

    Sorry Firefling, I cant remember which year yours is :oops:
  6. Not that it matters too much as it sounds as though the rain had something to do with it anyway.

    Likely to be water in the ignition causing a weak spark. Check the seals around your ignition coils and plug caps. Can be difficult to track down, but also spray everything liberally with WD40 (or some other moisture repellant). Next time it rains, carry soem with you, just in case.
  7. Firefling, I've heard that SV650s can be prone to problems in the wet - supposedly the ignition arrangements for the front cylinder are exposed to the weather.

    Dunno if that's the cause of your stalling, but it's probably a good place to start the investigation (WD40 in hand!).
  8. Mate it sounds like water in the petrol.EASY FIX, take a couple of caps of metho and throw in the tank. You see the water droplets cant pass through the jets so they stop the fuel from getting through and hence the stalling effect. The METHO apparently makes the water droplets smaller and hence it makes it easier to pass through the jetting system. Been doing it for years. Hope it works
  9. Nah, it's electrical, I'd put money on it.

    Ignition, certain of it.
  10. Don't think so, he said that he Had to put the choke on to prevent it losing the revs. But it jerked me forward a few times when it lost power then went back to normal..
    Sounds like fuel, electrical problems would not respond to the application of the choke
  11. Just as a fyi, firefling's a she. :)
  12. Still sounds electrical.
    One piston cutting out.
  13. A female eh, the name would be a great one to use for a drag queen
  14. If it cut out then I imagine that it wouldn't come back intermittently and so abruptly. My wonga is on the carbs.
  15. Thanks all, I'll try your suggestions and see how it goes :)

    I'll let you know how I go.
  16. If the voltage to the spark plugs drops slightly due to a partial short somewhere else in the system then the spark temperature will drop. In this case the choke would help as a rich mixture is easier to ignite. Same deal if the plugs are beginning to foul (although prolonged choke use will cause more fouling)

    If there is a problem delivering a spark to one cylinder then the choke would help and would also explain the jerking motion of the bike when the revs dropped (due to imbalance of the firing order caused by one cylinder incompletely igniting or failing to ignite)

    Lets wait for more info before being definite about the cause.
  17. Roll up, roll up, what's yer favourite.

    Carbs/ fuel or electrical, taking bets now....
  18. Rich mixtures tends to foul up plugs - that could add or disguise symptoms!

    I'm not making a stab at the problem... but wet plugs shorting out against the engine in wet weather could explain it... but why only at that time??? Why not during the whole ride?

    I'm curious now!

  19. On second thought, if I was flying and the cessna's engine started doing that, a prime candidate cause given the wet cold conditions would be carby ice - unfortunately, bikes don't have a carby heat.

    Did the bike start ok the next day?


  20. Dunno, haven't fired him up yet. Needed a bit more sleep so took the PT in :)