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1 petcock, vs 2

Discussion in 'The Garage' started by 52Chevy, Jul 24, 2012.

  1. 52Chevy

    52Chevy XS650 Addict

    From what I have gathered the older bikes had 2 petcocks with a fuel line going to each carb, whereas the newer bikes have only one, and the line T's off(like mine).

    Are there advantages to either set up?
  2. DogBunny

    DogBunny Motorcychologist

    The advantage of a single petcock is that your fuel delivery system will be half as complicated as a two-petcock set-up. There will be half as much chance that you will develop a leaky petcock. You will only need one fuel filter. Hose routing is simpler.

    I routinely convert two-petcock gas tanks to one petcock whenever I resurrect older XS650s.

    The disadvantage is that during low-fuel situations a small amount of gas gets trapped in the side of the tank without the petcock, but it is a very small amount, about two cups.
  3. 52Chevy

    52Chevy XS650 Addict

    I didn't think there would be a large difference. I figured there was a slight advantage to the newer set up, such as you stated being more simplistic.
  4. mrriggs

    mrriggs XS650 Junkie

    That's just the reserve-reserve so when you run out (because you forget to switch the petcock to ON when you last filled up) you can lean the bike to the left and transfer that little amount to the reserve. You'll probably still have to push the bike to the gas station, but you won't have to push it as far. :wink2:
  5. jd750ace

    jd750ace Front Toward Enemy

    That's at least 5 miles worth of gas, if you can get it re-primed!
  6. mrriggs

    mrriggs XS650 Junkie

    Unfortunately, if you made any left hand turns before running out then there may not be that much left in the reserve-reserve.
  7. jd750ace

    jd750ace Front Toward Enemy

    So it kinda sucks for flat track then? Dammit!
  8. 52Chevy

    52Chevy XS650 Addict

    Well that's good to know, I had also wondered how much had might be over there, and if there was a hose or anything connecting the two sides. I had not thought much about the fact that the verbs are gravity fed do an internal hose would do no good.
  9. DogBunny

    DogBunny Motorcychologist

    Well, it all depends on which petcock you keep and which you eliminate...
    Rutts likes this.
  10. jd750ace

    jd750ace Front Toward Enemy

  11. GreasyC

    GreasyC XS650 Addict

    There's a cross-over line on my rd to bring that stranded gas over to the single petcock on the left. Pain in the ass because the line runs UNDER the frame tube so you have to pull it to lift the tank and of course it doesn't have a tap to turn off the gas so you have to pinch the middle, pull the line off one side and quickly stop the leaking gas with your thumb, get the tank off with your hands busy stopping leaks then get the line back on the nipple before you can put it down. The XS is really a joy to work on in almost every way compared to my other bikes. Not being able to pull the head with the engine in the bike is the only real flaw in its layout. They didn't get that sorted until the xs750
  12. 52Chevy

    52Chevy XS650 Addict

    Yeah I have noticed everything is pretty simple. And pulling the heads in the bike would be great!! Oh well I'll take all the other simplistic things in trade of that one. After a few times of doing it the motor can be out in a matter of an hour or so.
  13. Milk_Jesus

    Milk_Jesus XS650 Addict

    I need to run some sort of T hosing for my dual bs 34's to my single petcock...recommendations???
  14. 5twins

    5twins XS650 Guru Top Contributor

    Stock BS34s have a T fitting between them and only take a single fuel line.

  15. bonesaw

    bonesaw Huney__Bear


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