Low Fuel Light

Discussion in 'Parallel Universe' started by HappyHighwayman, Sep 7, 2012.

  1. HappyHighwayman

    HappyHighwayman Been here awhile

    Joined:
    May 17, 2010
    Oddometer:
    312
    Location:
    San Francisco
    I find the fuel gauge system on the F800GS amusing. When the low fuel light comes on, I typically drive no more than 10-20 miles before refueling but often have as much as 1.1 gallons of gas left. Sometimes it's far less than that.

    it basically makes the gauge no better than having ONLY the low fuel warning light.
    #1
  2. Mr B

    Mr B Been here awhile

    Joined:
    May 16, 2009
    Oddometer:
    564
    Location:
    Merced, CA
    Agree!!
    I have gotten mine down to 12 miles till empty and when i gas up, it never takes more then 3.4 or 3.5 gallons, i know it says the bike has a 4.2 gallon tank with a 1 gallon reserve. I take the light to mean I am on the reserve gallon. One of these days I am going to clock the mileage and run it dry and see it the miles to empty can be trusted....I must say that the avg mpg is always accurate when you calculate.
    #2
  3. HappyHighwayman

    HappyHighwayman Been here awhile

    Joined:
    May 17, 2010
    Oddometer:
    312
    Location:
    San Francisco
    Unless you have different software than I do it only starts counting miles driven SINCE the light comes on, not "miles to empty".
    #3
  4. WoodWorks

    WoodWorks House Ape

    Joined:
    Feb 11, 2003
    Oddometer:
    2,204
    Location:
    Ashland, OR, USA
    That's what pre-2011 F800 and F650GSs did. BMW changed the software after that.

    And FWIW, I strapped a gas can to my bike and ran the tank dry intentionally twice a few years ago. Over a mixed range of roads, the "reserve" light came on at 185 and 188 miles, and the bike ran out of gas at 217 and 218 miles. Once the final bar on the gas gauge disappeared, it ran for another 10 miles each time.

    The most I've put in the tank without running it completely dry is 4.27 gals. And I'm pretty sure I wouldn't have made it another mile.

    But I have run the bike as long as 235 miles before the reserve light came on, so much depends on the speed you're running, headwinds, altitude, load of luggage, etc.

    Bottom line, adjust your mileage expectations with the conditions, and reset your trip odometer at each fill up. I wouldn't put too much trust in the fuel gauge, miles-to-empty indicator, or reserve light.
    #4
  5. HappyHighwayman

    HappyHighwayman Been here awhile

    Joined:
    May 17, 2010
    Oddometer:
    312
    Location:
    San Francisco
    I assume 200 miles per tank to be safe. I filled up at 175 miles today and guessed it would take 3.8 gallons and it was spot on.
    #5
  6. Loutre

    Loutre Cosmopolitan Adv

    Joined:
    Nov 28, 2010
    Oddometer:
    9,265
    Location:
    :o)
    it's like every useless gadjet. once we don't have it we miss it.

    It's a good "overview" product but a machine can't replace human reason. Just make an average out of it. I know that after 300kms I refill my tank weather the light is on or not.
    #6
  7. Moto_JJ

    Moto_JJ n00b

    Joined:
    Jun 7, 2012
    Oddometer:
    4
    Location:
    Sunny SoCal...for now
    Could be worse. Mine is telling me I have a full tank all the time. Luckily, they are going to fix it under warranty. Turns out it needs a whole new brain, as it wasn't just the sensors.
    #7
  8. sarathmenon

    sarathmenon Armchair Adventurer

    Joined:
    Mar 29, 2012
    Oddometer:
    1,450
    Location:
    SFO Bay Area
    I' ve had the bike stall bone dry once with 40 miles after reserve. And when I filled her, i got only 4 gallons in. Makes me wonder whether I got a smaller tank than ya'll. I typically get almost 200 to empty and these days I've wised up to fill it every 150 miles. Not really a rant or anything, but something's off with the guage for sure.
    #8
  9. MichaelRay

    MichaelRay Adventurer

    Joined:
    Dec 2, 2010
    Oddometer:
    16
    Location:
    Pittsburgh, PA USA
    My "bars" don't pop off full until about 140 miles and then drop like a rock. What are they supposed to do? My bike is still under warranty. Is this something I should have them replace?
    #9
  10. HappyHighwayman

    HappyHighwayman Been here awhile

    Joined:
    May 17, 2010
    Oddometer:
    312
    Location:
    San Francisco
    I think like most fuel related things on motorcycles they throw it on just to say they have it and put no effort into making it useful.
    #10
  11. Loutre

    Loutre Cosmopolitan Adv

    Joined:
    Nov 28, 2010
    Oddometer:
    9,265
    Location:
    :o)
    naaa... I think the problem comes from the tank and its architecture. it's not flat like tanks that are on top of the bike. the shape is not that even under the seat which causes problems.
    #11
  12. Angryrican

    Angryrican know nothing all

    Joined:
    Mar 10, 2011
    Oddometer:
    265
    Location:
    North NJ
    Mine came on last night and I rode 32 miles and it only took 3.2 gallons to fill it up. I've also notice the light comes on much sooner(130-140 miles) then on my 2010 F650GS
    #12