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When to turn fuel off?

Discussion in 'New Riders and Riding Tips' started by undii, Feb 23, 2005.

  1. Hi,
    I was just wondering what you guys think is a time period considered 'long' for the bike not to be used and the fuel cock to be put in off position? I.e should I need to put it into off position every night? And what about if the bike isn't being used for say 4-5 hrs. Does it make any difference at all if it's left in the on position most of the time (except for servicing and working on the bike?)

  2. Nah, leaving it on is fine. Recommendation is to turn it to off if leaving it for more than approximately a fortnight.
  3. thanks. Hope this helps others too :)
  4. As soon as you can reach over while they are not looking...
  5. There are some variations depending on the bike though too - if I left the fuel tap on on my old fzr250 the carbies would flood (or something anyways) within ~5 hours of being left. Thus starting the bike was an issue. I started turning my fuel tap off and the problem went away.

    (yes, this should not have been happening but I traced the problem to the fuel pump letting fuel through even when bike was off, and did not want to buy a new one).

    So if you are not having troubles leaving it on, then no worries. If you are (like I was) then perhaps turning it off is a good solution.
  6. When I bought my bike, was told that really should turn it off every night when putting it in the garage or shed. I do it just a matter of habit now. Apparently the fuel can go off in the carburetor and then can have problems starting etc. Not sure how long it takes for fuel to go off though.
  7. my bike did'nt come out with a fuel tap :(
  8. Fuel can go 'off' but it takes a few weeks / months depending on if its reg or the good stuff ( goes off quicker bc of all the additives etc )
    Yeah if your storing your bike turn the fuel tap off, or better yet drain the tank and carbies 1st, bearing in mind most later model bikes dont have a fuel tap at all.

    But if your bike is flooding overnight or after sitting for a few hrs, id be getting the needle and seats checked
  9. Same as nodz.

    I turn the fuel off each night when I get home. Force of habit now.
  10. I was told when I did my L's course in NSW to turn the fuel off every time you turned the ignition off. Since talking with another motorcycle instructor I would have to agree with the above mentioned comments about leaving the fuel on if its not a problem. The only draw back I've had with leaving the fuel on is one time when I needed to switch to reserve and the tap was tight from not being used.

    BTW I love the automatic censorship of cock, even when referring to fuel taps. maybe we should be grown up and call it a fuel penis. :LOL:
  11. Not always, I agree with draining the carbies if youre going to store the bike, but not the tank.

    A big metal container filled with normal air is the perfect place to form condensation. If you fill the tank as high as possible with fuel, then condensation can't happen (or is minimised) Better to put up with tank of easilly ditched stale fuel than water in a rusted tank.

    If your fuel tap and needle/seat (carbie bike) or injectors/fuel solenoid in an EFI bike are in good condition there's no need to turn the tap off. But it certainly wont hurt.

    JJ (just my two cents)
  12. The reason you turn the tap off on carb'ed bikes is that the seal formed by the needle and seat of the float valve is not always perfect under pressure (gravity). This os course is fine when the engine is running, but stop and the fuel will "leak" down the inlet manifold evenuntually into the cylinders (or sit on top of the valves if they're shut - but not all of them will be)....

    If the motor has been off for a short while then the motor may just be flooded and quite easy to start with wide open throttle....If however the motor has been off for a few weeks you will have fuel in your oil which is not a good this either from a lubrication or explosive point of view....

    Another thing that can happen with all that fuel (and fuel vapour) in the inlet manifold is that it can go...."BANG"....it can actually be a fire hazzard in some circumstances....

    So...bottom line...turn off your fuel taps (it takes what, 2 seconds?)....especially on older bikes which probably have worn float valves....

  13. Hmmm... On my bike ('92 ZZR250) I have three positions on the fuel thingy - on, reserve and "PRI" which I don't know what it means.

    Does anyone know what "PRI" means?????
  14. PRI == PRIMARY
  15. PRI - Prime. Where the tap bypasses the vacuum operated valve within the unit to prime the fuel system before starting. Usually used when the bike's been sitting a while, or the fuel system has been drained. Ensure that the carbies are full before you start cranking.

    And the vacuum operated valve works off engine vacuum to open and close the fuel "tap" when fuel is or isn't required.
  16. Its better to store a bike with a FULL tank of fuel to avoid the possibility of water/condensation/rust forming.

    I dont know about draining the carbies, what is there to keep all the gaskets and seals all nice and wet so they dont go brittle?
  17. That may eventually happen, But my bike (and a lot of others from the 90's on) has an electric fuel pump, so there's an extra set of valves to stop it. I don't turn the tap off, as it's never leaked (91 Across). But then again, I ride it every day, most it sits unused is two days, if I'm noty going to use it for a week or more, tap goes to the off position.

    Also, whenever I turn the ignition on, you can hear the pump prinimg the float bowls, if the tap leaked, the bowls wil remain full until the tank emptied completely. Also you'd notice the smell of petrol, every time you got on the bike.

    Flooding can happen if the tap leaks, I would think that fuel actually getting into the cylinder, while definately possible, you'd have to be real unlucky for it to happen. First symptom of that (apart from smell) is the piston will "hydraulically lock" when you turned the starter over.

    But like I said, it wont hurt to turn it off, so if that's your thing, go ahead.

  18. Good question, my answer (based on my car/truck mechanic experience)
    most of the seals/gaskets that are involved in a lot of float bowls are usually above the level of fuel So unless the fuel is slopping around while your riding, the seals are gunna dry out anyway.

    I suppose the idea is it's going to evaporate/leak in time anyway, might as well drain it and dispose of safely in the first place.....

    Or get an EFI bike and say... "who cares?" :wink:

  19. ok guys i did everything you said NOT to do lol i through my 95' zx6r in the shed for months this winter and didnt winterize it did nothing it DID have almost a full tank of gas, i took it out cause it was beautiful out today and it ran like crap finally figured out that (after draining the gas and puttin new gas in) one of the float needles most have gone bad when i turn the gas off it runs mint, when i turn it back on it runs rougher and rougher untill it stalls, so does anyone know exactly what i have to order and how to do it, i am pretty mechanically inclined just havent ran into this yet any help is much appreciated thanks!