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My petcock threw up—!

Discussion in 'The Garage' started by Vermont4me, May 13, 2023.

  1. Vermont4me

    Vermont4me XS400 Member

    Help please- my 81 xs400 is almost ready for new life- rebuilt carbs, reinstall fuel lines, vacuum line and boom, my petcock is leaking fuel- my bike hasn’t seen oil or car for 30 years so pretty sure the petcock seals are shot- is there an aftermarket petcock anyone can recommend that I can grab fairly quickly?

    thx-
    Bob
     
  2. tstidham

    tstidham XS400 Addict

    I put a purely mechanical one on my 78 off Amazon. I just posted the link in another thread, I'll see if I can find it.
     
  3. Vermont4me

    Vermont4me XS400 Member

    Thank you- being that my vacuum system still works (I think) will it interfere with the operation of the bike that you know if? Cheers
     
  4. tstidham

    tstidham XS400 Addict

    CaptChrome likes this.
  5. Vermont4me

    Vermont4me XS400 Member

    When you say ‘switched it’ you mean petcock right? Thx so much btw- it’s a huge help- looking forward to getting my 81 (3300 miles) ON THE ROAD!!
     

    Attached Files:

    tstidham likes this.
  6. Vermont4me

    Vermont4me XS400 Member

    Also, I have the original carbs (gummed up but intact…) is there a need for those on this forum? Classifieds? Cheers
     
  7. tstidham

    tstidham XS400 Addict

    Yes, when I removed the old vacuum petcock and installed this one to the tank.
     
  8. Vermont4me

    Vermont4me XS400 Member

     
  9. Vermont4me

    Vermont4me XS400 Member

  10. Vermont4me

    Vermont4me XS400 Member

    If I can ask one final question (mechanic I’m not…) so when I install the new petcock, I simply cap the vacuum nipple that previously had a hose on it to the petcock? Thx
     
  11. CaptChrome

    CaptChrome XS400 Addict Top Contributor

    Yes. Install the manual petcock and make sure that both of the vacuum nipples on the carb holders are capped off.
     
    tstidham likes this.
  12. Vermont4me

    Vermont4me XS400 Member

    perfect- thanks again
     
  13. Vermont4me

    Vermont4me XS400 Member

    Wow, what a journey, I (hope) that I’m almost there- new petcock arrived, installed it along with the new-old carbs, gassed it, sprayed the carb cleaner and it FIRED up after 32 years of sitting in a barn (oil is decent etc-) PROBLEM- the right muffler (which was heat colored when I got it..) appears to heat up and actually smoked a bit- have to adjust the idle speed tomorrow but the muffler smirking has me worried (btw, I ‘capped’ the vacuum nipples…) any ideas? Thanks so much!
     
    tstidham likes this.
  14. tstidham

    tstidham XS400 Addict

    I would check the valve lash first, then go about setting the idle mixture and idle speed. It may be lean on that side. But great news!
     
    CaptChrome likes this.
  15. Vermont4me

    Vermont4me XS400 Member

    Indeed, working on that today- thx for this also
     
  16. Vermont4me

    Vermont4me XS400 Member

    Ok my friend, for some reason I feel that you’ve ‘been there’ for this cycle rehab- new wrinkle, bike was running odd (mentioned the gas leak etc) so I removed the carbs (again, and btw, they were originals from eBay in seemingly good shape..)- upon closer examination the float was corroded right thru- question, is there a pair of new aftermarket carbs that you’d recommend I can snag to get this baby running again-
     

    Attached Files:

  17. Vermont4me

    Vermont4me XS400 Member

    Carbman Twin Carburetor Double Cylinder Carb Compatible with Honda Rebel 250 Carburetor CA250 CMX250 1996-2011 CMX250C 2003-2011 Carbs https://a.co/d/epO5Agv

    ????
     
  18. tstidham

    tstidham XS400 Addict

    Mikesxs does have a set of mikunis for the xs400 as a kit. I prefer the factory carbs myself. Maybe find some new floats?
     
    CaptChrome likes this.
  19. CaptChrome

    CaptChrome XS400 Addict Top Contributor

    I second the attempt to source some new(ish) floats for the original BS34 carbs. Other carbs will work, but you will have to be ready to spend a lot of time learning by trial and error to get them dialed in. The flat slides from Mikuni and Keihin are good choices, and there are a bunch of racers who use these on similar displacement bikes, but having carbs that Yamaha engineers already figured out is worth something.
     
  20. Vermont4me

    Vermont4me XS400 Member

    Appreciate your time, you have been wicked helpful- so yesterday, yeah, got the bike running and idling smooth but fuel kept rolling out of one side- i even ride the bike, felt good…took the carbs off, then apart and cleaned them, thinking maybe the initial ‘starting’ got em bunked up- put em back together and reinstalled them and didn’t even notice the hole in the float- took them back out and then I noticed- anyway, the seller from eBay was understanding and I really do feel it was an oversight so I found another set, ordered two rebuild kits and had to put off what I wanted to happen yesterday-:) lol-
     

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