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Float bowl never empties!

Discussion in 'Technical and Troubleshooting Torque' started by SaneForest, Feb 1, 2014.

  1. Hi,

    Had a few issues with my bike during a ride today. So after getting back, I decided to drain the fuel from the float bowl to be sure there was no water causing the issues.

    My bikes a a 2006 suzuki intruder vl250. The bikes got a vacuum type petcock/fuel pump.

    But as it turns out, the float bowl just dumps fuel for as long as the drain valve is open, at least half a litre or more(with the bike off) and it just keeps going.

    Where should I start? And how do I test the vacuum is working?
  2. Gravity feed mate. As long as there is fuel in the tank, it'll keep running down the delivery line.
  3. With a vacuum tap the fuel flow should normally be automatically shut off at the tank when the engine is stopped so whether it's gravity fed or not shouldn't matter a toss.

    Check that the fuel tap is not set to PRI. If it is, set it to MAIN or RES. If it isn't, you have a problem with the tap.
  4. Cheers PatB. That's what I thought. Just thought I'd double check to be sure there was nothing else going on.

    Guess I have some messing about to do then.

    Tas man, I see you're in hobart too. Nice to see another tassie in the forums!
  5. Just be aware that, on all the taps I've come across, the tap setting is the one which the long tag of the tap points to. I've been fooled a couple of times because I find this counter-intuitive, as I tend to see the tap in the manner of a weather-vane for some reason.
  6. Yeah, I always think of the long bit as the pointer, so it makes sense to me. There is a tiny arrow on it too. Though barely visible unless you get right up close. I checked it out and it's definitely broken. Fuel just flows out no matter which setting it's on.
  7. Well, it's off to the dealership for a fuel tap repair kit(which should contain all the necessary gaskets, o-rings and diaphragms to replace the perishables in the tap) then. Or a wrecker for the complete tap, although then you risk the replacement being equally buggered.

    Stripping the tap to replace all its bits should be a fairly straightforward screwdriver job.
  8. A repair kit sounds like the way to go. Thanks PatB (y)

    Now I just have to work out why it started cutting out at high revs/wot. Though, no sign of the problem now. So who knows.
  9. It's not impossible that it was something to do with the tap failure. fix the tap and see if the problem recurs.

    OTOH, if the problem was at high revs and WOT, are you sure you weren't just running into the rev-limiter?
  10. Tap first, then we'll see if it reoccurs.

    There's no rev limiter on my bike as far as I know. It was cutting in and out, when normally it would just stay on at wot and accelerate. It's never happened before.

    The cutting out only lasted a half hour, then I rode 80km home with out a problem. Maybe the petcock rubbers got stuck and blocked the fuel somehow.
  11. #11 Incontinentia, Feb 2, 2014
    Last edited by a moderator: Feb 2, 2014
    If fuel has been draining into engine, probably need to drain the sump and put fresh oil in. See if that fixes your WOT/rev problem.

    Have you also given thought as to why your float/needle/seat is allowing fuel to pass?
  12. The oil doesn't smell like fuel. But it's probably due an oil change anyway. I'll do it after the petcocks fixed.

    Yes, I did think about the float needle. It should only shut when full, right? So fuel should flow when I open the drain valve and let the fuel out. With the drain valve open and the petcock always on, won't the carbie continue to fill and empty? I might be missing something though...
  13. Ahh, yes.
  14. While it may not have a rev-limiter as such, everything I've ever ridden with electronic ignition has had a fairly well defined rev-ceiling, at which point the bike has developed what feels like a spectacular misfire and has refused to go any faster. Depending on the bike, it's been quite rough on occasion.

    Pre-electronic bikes would also fade at max revs if you were determined to play silly buggers with the redline but it was a more progressive process as either CB points or valves (or both) reached their limit and started to bounce :D.
  15. Ah, I see what you're saying. I'd say it definitely wasn't the rev-ceiling (though I do ride it very hard :D) I'd normally be able to ride around 110kph (give or take a bit) just fine but the problem was it couldn't rev high enough to get past 70. Then it just got progressively worse from there on until it couldn't move from stationery, but it could idle and maybe get to 1/4 (maybe half throttle). Eventually it just started working out of the blue.

    I was thinking bad fuel or a blockage. So maybe the petcock(seeing as how it's broken) got stuck and the fuel pump couldn't get fuel fast enough.
  16. #16 SaneForest, Feb 3, 2014
    Last edited by a moderator: Jul 13, 2015
    I went to my local dealer and there was no option to buy a repair kit and it was $110 for a new petcock. I didn't think that was a great price.

    So, I googled around and then I remembered an old youtube clip I'd seen called fixing petcocks without a rebuild kit. All I did was carefully stretch the small spring that presses the valve shut inside the petcock. No more leaking petcock. On, Res and Prime all work. Not sure how long this will last but it seems to be doing the job for now. Might have to check it after few rides just to be sure it's still working.
    • Winner Winner x 2