Post your BMW Airhead fuel economy

Discussion in 'Airheads' started by BrokenR80RT, Jun 18, 2011.

  1. RGregor

    RGregor Been here awhile

    Joined:
    Oct 31, 2007
    Oddometer:
    549
    Location:
    Bavaria
    Hello!

    One US gallon is 3.79 litres, right?

    The mileage of my bike is:
    59mpg (4 litres per 100 km) if I go rather slow (within the speed limits)
    47mpg (5 litres per 100 km) if I push the bike

    Engine is a modified Siebenrock 1070.

    Best regards

    RG
  2. Bulldust

    Bulldust Bulldust

    Joined:
    Jun 7, 2007
    Oddometer:
    837
    Location:
    Australia
    My 1981 R100CS gets 500 miles to a tank (800 kilometres).
  3. RGregor

    RGregor Been here awhile

    Joined:
    Oct 31, 2007
    Oddometer:
    549
    Location:
    Bavaria
    Hello!

    What tank do you have?
    79mpg sound incredible.

    Best regards,

    RG
  4. Bulldust

    Bulldust Bulldust

    Joined:
    Jun 7, 2007
    Oddometer:
    837
    Location:
    Australia
    45 litre Heinrich
  5. blaine.hale

    blaine.hale Long timer

    Joined:
    Feb 28, 2009
    Oddometer:
    3,575
    Location:
    Atlanta, Ga
    Pretty important little fact :lol3
  6. DaveBall

    DaveBall Long timer

    Joined:
    Sep 30, 2009
    Oddometer:
    1,165
    Location:
    Vancouver Island
    Don't muddy the waters with facts. :rofl

    My 79 R100RT would average 50 miles per Imperial gallon.
    My 81 R100RT still averages 47-50 miles per Imperial gallon.
    The wife's little 1980 R45 has never gotten less than 65 miles per Imperial gallon.
  7. darklight79

    darklight79 drink it , ride it , nail it

    Joined:
    Jun 2, 2010
    Oddometer:
    1,186
    Location:
    Eureka ,Calif
    In oregon to the rally much to my surprise running with starbrite blue . Running 45 268 145. I pulled 45 mpg. Which never happens running calif fuel usually mid to low 30s. But then i was traveling the speed limit. Which almost never happens
  8. orangebear

    orangebear Long timer

    Joined:
    Aug 12, 2010
    Oddometer:
    1,377
    Location:
    dumfrie scotland
    With my r100gs i just work out miles per tank which was about 200 to 260ish with a taller 5th gear. No idea what mpg/ mpl it does
  9. JasonH

    JasonH Been here awhile

    Joined:
    Jul 5, 2005
    Oddometer:
    212
    Location:
    McKinney, Texas
    I wish I could figure out how to get to these 40mpg numbers. I was getting a very consistent 20mpg. Then I recently dropped the slide needle one notch and it got to around 30mpg. I guess I could drop it again, but I'm gonna watch the plugs for a while first.
  10. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
    Oddometer:
    9,116
    Location:
    San Francisco Bay area
    Get your bike tuned up right and ride REAL slow.

    I got my all time record of 42mpg with a sport cam, 8.5:1 CR, and Dellorto's. I rode just over the speed limit for a couple of days. Cruising around 80-90 mph I have always got around 36mpg whether it was a R65 or a R100. Even with my cam and carbs in my R100 although it would drop to the low 20's when hauling the mail in the mountains. Now I am getting 30mpg cruising 80-90mph after raising the CR to 10.0:1, dual plugging it, giving it a major port job, majorly modifying the airbox, and putting thick wall 4130 pushrods in it with the same cam and carbs as before but man am I making a LOT more power now when I turn the throttle!
  11. Wirespokes

    Wirespokes Beemerholics Anonymous

    Joined:
    Jul 26, 2002
    Oddometer:
    8,690
    Location:
    Jackson's Bottom Oregon
    A lot depends on the rider's weight, so be sure to factor that in.
  12. Ray R

    Ray R Been here awhile

    Joined:
    Dec 27, 2006
    Oddometer:
    951
    Location:
    The OC, OR
    Oh crap! I'm screwed! :rofl
  13. 53dodgekustom

    53dodgekustom Been here awhile

    Joined:
    Apr 5, 2012
    Oddometer:
    108
    Location:
    Waterloo, IL
    My 71 R60/5 with 30mm Delorto's gets an average of 37 mpg I'd say. Riding between 60 and 70 mph. I have gotten a best of 52 mpg riding 45 mph following a slow /2. Riding 2 up into the wind trying to go 75 mph results in 28 mpg.

    [​IMG]


    My dad's airheads are two extremes. The R26 on the left has gotten a best of 70 mpg putting around on backroads. The R50/2 with the heavy Ural sidecar gets about 20 mpg. Both are happy at 50 mph and are ridden at WOT A LOT to keep up with traffic!!!!

    [​IMG]
  14. LoneRanger

    LoneRanger Adventurer

    Joined:
    Sep 5, 2008
    Oddometer:
    53
    Location:
    Lewistown, Montana
    I'm averaging 44.4 mpg with my 1980 R100T.

    [​IMG]
  15. jbf

    jbf ???????????????????!

    Joined:
    Apr 30, 2012
    Oddometer:
    43
    Location:
    Los Angeles, CA
    Damn, seems like most people with quite high MPG on their R75/5s.


    I'm only getting an average of 35.8 MPG right now. Carbs have been rebuilt and synced. They might be running a tad rich, but besides that what else could contribute to loss of fuel economy?


    I weigh only around 180-85lbs and ride mostly solo with little to no extra baggage.

    Running with california 91 octane with 10% ethanol.
  16. R100RTurbo

    R100RTurbo Esoteric by Choice

    Joined:
    May 23, 2014
    Oddometer:
    599
    Location:
    BC
    5.7 liters/100km (Canada Hey)
    This is fairly consistent, with heavy roll on sessions mixed in with combined city/hwy.
  17. BMW851

    BMW851 Piston Broke

    Joined:
    Dec 4, 2010
    Oddometer:
    129
    Location:
    Blue Mountains, Australia
    1988 R100RS

    Average fuel consumption

    5.8 L/100
    48.9 mpg Imp. Gallon (4.546 Litres)
    40.7 mpg US Gallon (3.7854 Litres)

    Mostly just cruising along on a 210 Km loop I do through the local mountains.
  18. Beezer Josh

    Beezer Josh Moto-Amish

    Joined:
    Jan 19, 2013
    Oddometer:
    1,525
    Location:
    15.6 miles from the U.S. Capitol
    Alright guys, two weekends ago I rode 1500 miles in 3 days on my '73 R75/5. I checked gas mileage at every stop. My best fuel consumption was 42 MPG, worst was a little over 38. This makes absolutely no sense to me, but when I held a relatively steady 55 MPH in 4th gear on flat roads, I got the worst gas mileage. My best gas mileage was flogging it in the sweeping curves in the Adirondacks, going 60 in 3rd gear with two loaded panniers. I also found oil consumption to be the inverse: the bike ate oil while flogging it, didn't seem to lose a drop when on the flat roads.

    So, my best ever on my /5 is 42 MPG (US). Worst was about 33 when I raised the needle position and enriched the mixture. I'm 6'2" and weigh about 225.

    <s>Does anyone know if the values quoted in the owner's manual are US MPG or Imperial MPG?</s>
    Nevermind, it says MPG US. It was a vain hope that I was nearing the 52.3 they mention in the book...
  19. mendoje

    mendoje Been here awhile

    Joined:
    Jun 6, 2009
    Oddometer:
    279
    Location:
    Los Angeles
    On my 81 R100RS, long since gone, a lifetime ago I got 44 mpg, no matter what, about 75% freeway vs 25% surface streets.

    On my current 86 R80 G/S, about 35 mpg for the same type of driving.
  20. MotorcycleWriter

    MotorcycleWriter Long timer

    Joined:
    Dec 1, 2012
    Oddometer:
    1,596
    Location:
    North Alabama - World's Rockiest Trails
    '89 R100GS, 28K miles, mostly city riding, 93 octane gas, hot weather, 39 mpg.