Page 1 of 2 1 2 LastLast
Results 1 to 15 of 18

Thread: Gas leaking out of vent hoses

  1. #1
    Registered User
    Join Date
    May 2018
    Location
    Thousand Oaks, Ca.
    Posts
    33

    Gas leaking out of vent hoses

    So just recently at fuel up gas will leak out of both tubes until the fuel level in the tank gets lower. Made me think the in bed vent hoses came loose. I opened the tank and the lines are secure top and bottom. I didn’t blow air through the hoses at the time but a hole in the hoses, both of them, can be the only reason, am I right about that?

    Thanks.

  2. #2
    Registered User dieselyoda's Avatar
    Join Date
    Mar 2013
    Location
    Winnipeg, MB, Canada
    Posts
    1,481
    Happens to me: Fill tank right full with cold fuel, add heat from the sun when parked=gas puddle.

    I just adjust how much fuel I put in when I know the bike will be parked for a time or I fill it right full and then turn the throttle and go through the gears until I need more fuel or stop to pee.
    1997 R1100RT, 1981 KZ 440 LTD, R80RT, R90/6 sidecar, K1100RS,1983 K100RS (Cafe now)

    “The major civilizing force in the world is not religion, it is sex.”

  3. #3
    Fortis Fortuna Adiuvat Omega Man's Avatar
    Join Date
    Jan 2010
    Location
    Mansfield,MA
    Posts
    14,269
    Is that the deal that saturates the canister? Filling the tank extra full?
    OM
    "You can do good or you can do well. Sooner or later they make you choose." MI5
    Mod Squad
    2009 F800GS 1994 TW200

  4. #4
    Registered User GTRider's Avatar
    Join Date
    Apr 2006
    Location
    Nibley, UT USA
    Posts
    1,203
    Quote Originally Posted by mykrs View Post
    So just recently at fuel up gas will leak out of both tubes until the fuel level in the tank gets lower. Made me think the in bed vent hoses came loose. I opened the tank and the lines are secure top and bottom. I didn’t blow air through the hoses at the time but a hole in the hoses, both of them, can be the only reason, am I right about that?
    I would suspect the two vent hoses submerged inside the tank. They may still be fastened tightly at their ends but the hoses may have cracked from age. Note that if you decide to replace them you’ll want submersible-rated (SAE 30R10) hose. Those lines are 5mmID x 10mmOD; bulk line is available in one-meter lengths from BMW. New clamps are a good idea, too—the OEM Oetiker clamps are a pain to work with but do the job well.

    Best,
    DeVern
    Last edited by GTRider; 10-09-2019 at 02:55 AM. Reason: Fix hose size
    DGerber
    1983 R80ST — 1984 R80 G/S-PD — 2004 K1200GT w/Hannigan S/C — 2010 K1300GT — 2018 R1200GS
    BMWMOA#52184, AMA#271542, IBA#138

  5. #5
    Registered User GTRider's Avatar
    Join Date
    Apr 2006
    Location
    Nibley, UT USA
    Posts
    1,203
    Quote Originally Posted by Omega Man View Post
    Is that the deal that saturates the canister? Filling the tank extra full?
    OM
    Several things can do that. Filling the tank until fuel nearly overflows the “biscuit” vent-separator in the tank can do it, tho it is physically difficult to fill a tank that full. Other causes can include a biscuit that has fallen loose, a cracked or broken purge hose inside the tank (the one that’s connecting the cannister to the biscuit), a broken/dislodged/missing/poorly-replaced clamp on the purge line inside the tank, or misconnected vent and purge hoses (cross-connected). That latter one can contaminate the cannister with H2O draining down from around the fuel cap.

    But if one has a saturated cannister the usual approach is not to check the above, but to do a cannisterectomy. Which of course leads to that faint hint of gas fumes in the garage the morning after a fuel-up, and the nagging worry as to how that meshes with the gas-fired water heater mounted in the garage. But, I digress.

    Best,
    DeVern
    DGerber
    1983 R80ST — 1984 R80 G/S-PD — 2004 K1200GT w/Hannigan S/C — 2010 K1300GT — 2018 R1200GS
    BMWMOA#52184, AMA#271542, IBA#138

  6. #6
    Registered User dieselyoda's Avatar
    Join Date
    Mar 2013
    Location
    Winnipeg, MB, Canada
    Posts
    1,481
    Or, It could be as simple as the tank is plastic, you put cold fuel in it, it shrinks, the sun warms it, the tank expands, so does the respective volume of fuel, pressure builds, exceeds the fuel cap relief capacity or even the fuel tank volume?
    1997 R1100RT, 1981 KZ 440 LTD, R80RT, R90/6 sidecar, K1100RS,1983 K100RS (Cafe now)

    “The major civilizing force in the world is not religion, it is sex.”

  7. #7
    Registered User
    Join Date
    Jul 2018
    Location
    Corralitos, CA - Santa Cruz County
    Posts
    114
    This happens to me only when I have filled to the top in morning on way into work and I leave on side stand instead of on center stand. No over flow on center stand.
    Signature

  8. #8
    Registered User GTRider's Avatar
    Join Date
    Apr 2006
    Location
    Nibley, UT USA
    Posts
    1,203
    Quote Originally Posted by chrisinsc View Post
    This happens to me only when I have filled to the top in morning on way into work and I leave on side stand instead of on center stand. No over flow on center stand.
    That makes sense. On a full-to-the-top fillup, putting the bike on the sidestand dips the biscuit into the fuel and even tho the vent hole is on top of the biscuit it can be submerged and drain raw gasoline into the canister.

    Best,
    DeVern
    DGerber
    1983 R80ST — 1984 R80 G/S-PD — 2004 K1200GT w/Hannigan S/C — 2010 K1300GT — 2018 R1200GS
    BMWMOA#52184, AMA#271542, IBA#138

  9. #9
    Registered User
    Join Date
    May 2018
    Location
    Thousand Oaks, Ca.
    Posts
    33
    Well I have filled the tank with just 3 gallons of gas and I still get the leak...so I have to assume that BOTH of the vent hoses in the tank have cracked at the same time? They're both connected top and bottom to fittings. So, that's my working theory.
    Now...
    Has anyone discovered submersible 5mm vent hose for less than $20 a foot? and I'm assuming I need 3 feet. Yikes!
    Thanks!

  10. #10
    Registered User
    Join Date
    Jul 2018
    Location
    Corralitos, CA - Santa Cruz County
    Posts
    114
    I use BMW Motorworks UK for almost all my parts even though I am in the US. 2 day service for very reasonable prices. They also have a large selection of used parts.
    Signature

  11. #11
    Registered User
    Join Date
    May 2018
    Location
    Thousand Oaks, Ca.
    Posts
    33
    Quote Originally Posted by chrisinsc View Post
    I use BMW Motorworks UK for almost all my parts even though I am in the US. 2 day service for very reasonable prices. They also have a large selection of used parts.
    Thanks! I wasn't aware of them before. Will be giving them a look.

  12. #12
    Registered User roger 04 rt's Avatar
    Join Date
    Oct 2011
    Location
    Florida & Massachusetts
    Posts
    1,990
    Quote Originally Posted by mykrs View Post
    Well I have filled the tank with just 3 gallons of gas and I still get the leak...so I have to assume that BOTH of the vent hoses in the tank have cracked at the same time? They're both connected top and bottom to fittings. So, that's my working theory.
    Now...
    Has anyone discovered submersible 5mm vent hose for less than $20 a foot? and I'm assuming I need 3 feet. Yikes!
    Thanks!
    You’re on the right track now. I got a one meter length of hose from max bmw, that I cut in half and it just fit.

    When did you last replace the u-shaped hose?

  13. #13
    Registered User
    Join Date
    May 2018
    Location
    Thousand Oaks, Ca.
    Posts
    33
    Quote Originally Posted by roger 04 rt View Post
    You’re on the right track now. I got a one meter length of hose from max bmw, that I cut in half and it just fit.

    When did you last replace the u-shaped hose?
    I never replaced the ushaped hose. I just got the bike.

    Max BMW, thanks, having a look. I went to a used bike shop today and bought some stuff for my bike at great prices and damn if he didn't cut those hoses when he removed the fuel pump to sell it. But i got a clean wind shield for $20, so that was a win.

  14. #14
    Registered User
    Join Date
    May 2018
    Location
    Thousand Oaks, Ca.
    Posts
    33
    Ordered hose from motor works in the UK. Even with shipping, how can it be cheaper than the US? It is, so I’m trying them out. Will update.

  15. #15
    Registered User
    Join Date
    Aug 2006
    Location
    Southern California
    Posts
    143
    For future reference.
    They have most everything, and located in Denver.
    Link:
    https://www.euromotoelectrics.com/category-s/2999.htm

Similar Threads

  1. 2004 R1150R with all vent hoses looped
    By onasteelhorse in forum Oilheads
    Replies: 6
    Last Post: 09-18-2018, 05:26 PM
  2. In tank vent hoses
    By 179212 in forum Oilheads
    Replies: 5
    Last Post: 05-15-2017, 02:51 PM
  3. 90 K75S vent hoses
    By jwetering in forum Flying Brick K-bikes
    Replies: 5
    Last Post: 02-12-2012, 03:52 AM
  4. Fuel vent hoses in the tank- how to replace
    By cb75076 in forum Oilheads
    Replies: 4
    Last Post: 07-21-2008, 01:44 PM
  5. 95 R100rt tank vent/overflow hoses
    By mikegates in forum Airheads
    Replies: 2
    Last Post: 03-06-2008, 03:35 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •