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Eric's picture
VBMWMO #9227
Joined: 10/07/2011
Posts: 3

Hi, Thinking about using aviation fuel in my R69S and 78 R100RS. Superior octane, no ethanol, led lubricates valves, fuel last longer without going stale. Does anyone know of a negative draw back to trying this? For $5.95 per gallon, it's expensive and but I don't put many miles on these bikes - my daily rider is an oil head. Thanks! Eric

stagewex's picture
VBMWMO #8810
Joined: 10/26/2014
Posts: 464
I use non-ethanol 97 or 100

I use non-ethanol 97 or 100 octane in all my bikes during the real cold months of Jan & Feb. I don't know if that qualifies it as being "Aviation Fuel"?
I do ride during the Winter but with multiple bikes and work it's rare that I'm going to be putting more than a couple hundred miles on any of them.
I've found no downside but then again never found a downside with Seafoam or Stabil either.
I own a r60/2 so not the high compression engines of the "S" models. Rest of the year I use 87 octane but she'll run fine on just about anything.


mike wex/stagewex
1969 BMW r60/2, US Model, 1995 BMW K75, 2006 Yamaha TW200, 2007 Ural Patrol

schrader7032's picture
VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6540
If it is aviation fuel sold

If it is aviation fuel sold at a local airport, it is technically illegal to use it in road vehicles. I'm sure there are some laws but some of it is that the road taxes have not been paid on the fuel.

Prior to the top end on my /7, I played all the games to try and get the right fuel or additive to "protect" the valves. I bought VP leaded racing fuel in 5 gallon drums and put a little in each tank. But working with actual leaded gas was somewhat troubling...not to mention a real hassle. Then I used various additives like ValvTect, DurAlt, and others. On long trips, I'd have to make sure I carried enough of the additives and find it deep in my saddlebag to add to each fill up. Such a royal pain. I began to have a slight pucker factor that my valves might let go at around 100K miles. Couldn't ride around with that mental anguish any more. So, I opted to do a top end which included sending the valves off to Ted Porter. Now I have trouble free and anguish free riding. Whew!!

That's my story and I'm sticking to it!!


Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

JakeF's picture
VBMWMO #9236
Southern California
Joined: 12/02/2016
Posts: 82
Aviation fuel

For my '56 R69 I run 91 octane and add Motor Medic brand lead substitute. My nearest gas station sells 101 octane race fuel which I have also used but at $9.95/gal I am too cheap to use it regularly. It did run a shade quieter on the 101. Like you I have thought about trying aviation fuel. I live just a few miles from an airport with a large private plane contingency but have not bothered to try and see if they would sell me gas. Please report back on the forum if you do try it.


1956 R69, 1976 R90S, 2008 R1200GS

Captonzap's picture
Joined: 08/21/2014
Posts: 55
Shhhhh, not so loud

The 100 Low Lead aviation gas has about four times as much lead as the old regular leaded gas. So one part Avgas to 3 parts unleaded should give you about the same protection. The alcohol is another story, but if you don't let it set around to long, or find a marine gas pump and get that gas, which doesn't have alcohol in it, you should be OK.
If you know anyone who is into the homebuilt aircraft hobby, ask them if you can use their N number to buy gas. Tell the line boy that you are doing stationary runup, and can't bring the plane to the pump. A lot of smaller airports have a credit card reader on the pump, since they can't afford to hire full time attendants, so then there is no problem.
Is it against the law? Let me quote one of our past supreme leaders. "It depends on what the definition of 'is' is." WJ Clinton, circa a while back. LOL

Goomicoo's picture
Studio City Ca.
Joined: 02/26/2012
Posts: 24

I don't know about other states but you can buy Ethanol free fuel at the pump in Wyoming. The octane tops out at 91 which should be fine unless you've got high compression pistons. Avgas was never a problem when I worked at the airport. But the lead paste in the oil pans made me think twice about using it on a motor with slingers.


'64 R69s
'66 R60
'67 R69s
'68 R50

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