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Thread: 1980 RT 100 fuel reserve issue

  1. #1

    1980 RT 100 fuel reserve issue

    Hello! I have a 1980 RT100 that runs well except when it runs out of gas on the main tank and you switch over to reserve tank it won't deliver the gas. Would this be a pinched crossover line? Thank You for your help!

    Best Wishes, Bob

  2. #2
    Liaison 20774's Avatar
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    Bob -

    I think more likely, that the straws that stick up from the petcock inside the tank have fallen off. So, when you're on the "main" tank, in fact you're drawing from the bottom of the tank. On this page:

    http://w6rec.com/duane/bmw/petcock/

    you'll examples of these tubes. I think you're going to need to pull the petcocks and confirm.

    When you've run out of gas, how many gallons did it take to fill the tank? If it took around 6 gallons, then the above is the problem. If it took say 4.5-5 gallons, then you still have something going on. Could be that the straw for the "reserve" is plugged.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #3
    Registered User ebeeby's Avatar
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    Quote Originally Posted by 20774 View Post
    Bob -

    I think more likely, that the straws that stick up from the petcock inside the tank have fallen off. So, when you're on the "main" tank, in fact you're drawing from the bottom of the tank. On this page:

    http://w6rec.com/duane/bmw/petcock/

    you'll examples of these tubes. I think you're going to need to pull the petcocks and confirm.

    When you've run out of gas, how many gallons did it take to fill the tank? If it took around 6 gallons, then the above is the problem. If it took say 4.5-5 gallons, then you still have something going on. Could be that the straw for the "reserve" is plugged.
    +1 or the straw screen is clogged on the reserve.
    1973 R75/5

  4. #4
    Registered User tanker4me's Avatar
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    Straws?

    +2 on the straws. I ran out of fuel on a '76 R90/6 1st reserve because of the straws not being in place on BOTH petcocks!
    I had put the "spare" stock tank on the bike not knowing the straws were dislodged.
    We are all here for a spell, get all the good laughs you can.
    Will Rogers

  5. #5
    Just a thought. The "straws" ideas above are the first likely culprit.

    But, when I did my R100/7 I removed the tank and then petcocks and there was so much gunk down there that the "reserve" flow could have been hampered if it had gotten worse. Be sure that all that is totally cleaned out.
    "The difference between death and taxes is that death doesn't change every time congress meets." - Will Rogers

  6. #6
    Registered User kentuvman's Avatar
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    I've been sorting out a new to me '76 R60/6 that sat a long time with fuel in the tank - one of the tasks was overhauling the petcocks - there's a really useful how to video on You Tube that helped a lot - I bought the rebuild kit on Ebay from Capital Cycle - had to do the left side 2x as once gas was added to tank, it was not shutting off - turns out eve though I'd run it through the ultrasonic cleaner for about 45 minutes, there was still brown residue (probably ethanol or just bad gas) that was stock inside the metal holes.

    I'd pull both, get the kit and watch the video to get it right.

    Here's the link to the video on You Tube

    https://youtu.be/JU_9f7J4JP8
    Ken Tuvman
    Excelsior, MN
    K1200GT & R65LS

  7. #7
    Registered User tanker4me's Avatar
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    Straws? Continued

    SCBuckeye/kentuvman

    aba24500f4e2359caca124486292a43a.jpg
    Whaaat are you doing here?
    Anywell, I was on the 405 when I ran out of gas at Century, I coasted down the onramp, pulled the tank and walked under the 405 to the Chevron station at La Cienega, went back to the bike then up La Brea to Sunset over to PCH to Topanga then turned right on Ventura all the way to where it turns into Cahuenga followed that to the 101 then got off and took Figueroa all the way home. I put the Heinrich tank back on the bike and procured petcocks from Irv Seaver BMW for the old tank. 40 bucks apiece. (they had them in stock)
    And thats the truth!

    Disclaimer; I don't watch TV much, 2 weeks ago didn't know who Bill Hader or Fred Armisen were! Watched a Youtube clip of Hader on Late Night explaining the origins of the Californians SNL skit, then watched the 1st one and had a good laugh.

    Anywell, I left out La Tijera, Centinela,, Bundy, Normandie, Pico and Sepulveda.

    Apologies to Flo & Eddie, Bill and Fred.
    Bill
    Last edited by tanker4me; 06-02-2018 at 01:08 AM.
    We are all here for a spell, get all the good laughs you can.
    Will Rogers

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