R80 Gas tank

Discussion in 'Airheads' started by gerrynj, Apr 16, 2012.

  1. gerrynj

    gerrynj Been here awhile

    Joined:
    Oct 17, 2005
    Oddometer:
    259
    Location:
    NJ
    I bought a '86 R80RT a while back and based on the reviews I have read - I thought I had a >5 gallon tank. Well - I found out last week, that I do NOT have a >5 gallon tank. I almost ran out of gas after a 120 mile ride.

    So this past week-end I emptied the tank completely and refilled it with 3.9 gallons of gas. Do I have an odd sized tank (it looks like the original) ? or was there an option when the bikes were new?

    thanks
    Gerry
    #1
  2. supershaft

    supershaft because I can

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    Mine holds about 5.9 according to the pump the one time I had it completely empty. You have got to take the flap out to fill it that high. I have put 5.7 in it quite a few times.
    #2
  3. Boxer Metal

    Boxer Metal Mad Scientist

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    Some of the post 85 tanks have a flap in them that do not allow you to fill them up all of the way.
    #3
  4. Airhead Wrangler

    Airhead Wrangler Long timer

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    Are you sure you really drained it? Reserve on both petcocks? 3.9 is way small.
    #4
  5. bmwloco

    bmwloco Long timer

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    It could have an R65 tank on it. That's the only one I can think of that has such a tiny tank in the "modern" boxer era.
    #5
  6. supershaft

    supershaft because I can

    Joined:
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    My R65 tank held just a few tenths less than my Mono tank.

    I don't remember the exact method I used to remove the flap. I think I bent it and broke it off with some long needle nose pliers and then folded it up with the same pliers inside the tank and removed it out through the top.

    Real soon I am planning on removing the entire welded on neck extension for the flap. I think then I will get a couple of more tenths in it. The internal vent might be an issue that full but I will soon find out. I don't want to do away with the internal vent since I always have a tank bag on and I really appreciate the cap not venting and filling up my tank bag with fumes. That's a great feature of an otherwise not so great system.
    #6
  7. mark1305

    mark1305 Old Enough To Know Better

    Joined:
    Feb 7, 2005
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    Location:
    Merritt Island, FL
    My R 80 ST tank is supposed to hold 5 US gallons according to the manual. I think I was only able to squeeze 4 or 4.1 into it after draining it.
    #7