Fuel Question

[MACDADDYBMWR1200RT]

Hey I've got a good question for Y'all, if BMW recommends 91 or better octane for the R1200RT, could you run 94 octane Ethanol 85 in it?

[Tom K.]

Hey I've got a good question for Y'all, if BMW recommends 91 or better octane for the R1200RT, could you run 94 octane Ethanol 85 in it?

Actually, BMW recommends 93 pump octane. So let us know how your RT runs on E85.

[deilenberger]

Hey I've got a good question for Y'all, if BMW recommends 91 or better octane for the R1200RT, could you run 94 octane Ethanol 85 in it?

I wouldn't do that. The fuel system wasn't designed with E85 in mind.. It might run - for a while (and where you you find 94 octane E85?)

[MACDADDYBMWR1200RT]

In Kansas at the pump, the octane label says 94. What's interesting is that the manual is unclear as to what you can run in your bike. Even though it recommends 91 or better octane, it states that you can run other grades with different results, or something like that ( I don't have manual here to look at.)

[greenwald]

Recently attended a Tech Session at my BMW dealer for oilheads. Subject of fuel was discussed, and basically the advice was as follows:

Avoid any ethanol fuel greater than 10% in oilheads (2005 or newer) and use premium fuel (octane ratings may vary but premium fuel recommended).

While the engine computer/oxygen sensors can 'compensate' for medium-grade fuels with lower octane ratings, you've bought the 'swiss watch' of motorcycles - don't get your batteries for it at the Dollar Store.

Ride Alert!

[RIDERR1150GSADV]

IIRC most 'older' BMW's are designed for use of 89 octane gas with perhaps the new K engines for higher rated octane gas.
I have run all my bikes , boats and cages on 87 or 89 octane and never had any issues. I also rarely redline the engines either or expect maximum power from them running this type of fuel. Spending extra $$ on higher octane is a waste of money if the engine is not designed for it. If you take it easy on the engine(s), you can get away with a lower octane fuel. If you do hear pinging than you need to step it up a notch from what you have been using. Higher octane does NOT provide more power. It is a anti-knock index not a HP index. Just my 0.02 cts. YMMV.

[100394]

IIRC the biggest problem with E85 fuel is that an ethanol content of more than 10% can damage rubber components in the fuel system. Many automobiles cannot run ethanol for this reason. I would play it safe and avoid it.

[Tom K.]

IIRC most 'older' BMW's are designed for use of 89 octane gas with perhaps the new K engines for higher rated octane gas.
I have run all my bikes , boats and cages on 87 or 89 octane and never had any issues. I also rarely redline the engines either or expect maximum power from them running this type of fuel. Spending extra $$ on higher octane is a waste of money if the engine is not designed for it. If you take it easy on the engine(s), you can get away with a lower octane fuel. If you do hear pinging than you need to step it up a notch from what you have been using. Higher octane does NOT provide more power. It is a anti-knock index not a HP index. Just my 0.02 cts. YMMV.

My 1976 R75/6 was designed for the 95 pump octane available in those days. It would detonate badly above 4,000 rpm on 92 octane which is why folks compensated with thicker base gaskets or dual plugged heads in the early 1980's when U.S. octane began to decline.

And yes, higher octane does provide more power if the engine is designed for it. The hexheads are and use a knock sensor to adjust the timing for lower octane gas, reducing both power and fuel mileage. The owner's manual for my '06 RT clearly claims 110 hp when using 98 RON octane fuel - 98 RON being equivalent to 93 (R+M)/2. It also specs 101 hp when using 91 RON (equal to our 87 pump.

[njnear]

12:1 pistons.... I think 91 is a little low even though the manual says it's OK. I avoid putting anything in it that's less. Yes the computer will keep it from spark knocking, but I wouldn't chance it on a regular basis.

As for the E 85, the seals/gaskets etc. won't handle all the alcohol (as stated above). E 85 is a different density than gasoline, so your metering system (not carburation) will likely not function properly. On top of that you'll get about 2/3 of the BTU's of gasoline and performance would suffer (including gas mileage).

[screamineagle]

I am not an expert on fuel but what I have heard is the E85 fuel is much less efficient so that even though it is cheaper per gallon, when you do the calculations it cost the same per mile as galoline. If that is true (I don't know) why use it.

[thartman]

I sure notice it. I get 250 miles on a tank full of 93 octane but less than 170 miles if I have to use a lower octane. I do run at between 4,000 rpm and 5,000 rpm so maybe that hurts me. I was running on empty yesterday and filled it up with 91 octane then at half a tank topped off with 92 octane the highest I could find. Finally found a station with 93 and topped it off again. I ended up getting 164 miles on that tank before my "42 miles to go" warning came on.

I can repeat it every time, which I try not to do but it is hard to find 93 octane so I get to test it more than I like.

[cjack]

Hey I've got a good question for Y'all, if BMW recommends 91 or better octane for the R1200RT, could you run 94 octane Ethanol 85 in it?

NO. BMW specifically said (in some SB that I recall) they will not be responsible for faults caused by E85 and recommends a maximum of 10% Ethenol.

[grafikfeat]

E85 eats gaskets, gasket sealants and rubber.

I ride a 2002 R1200c and run 87 octane. When I was using 89 and above I got 37-40 mpg. I went to 87 it went up to 43-48 and even broke the 50 mpg mark. It won't happen on one tank so run about three and you will see a change. If you get pinging go back to what you were running. But there is NO need to run hi-test. Waste of money.

But for me... I'll put that nickel in MY pocket before I give it to the rat bastard oil companies.

[greenwald]

We have that E-85 crap here in WI.

15% gasoline, 85% 'corn crap.'

Big loss of power & harsh on seals and gaskets.

Avoid it like the plague!

[easy]

IIRC the biggest problem with E85 fuel is that an ethanol content of more than 10% can damage rubber components in the fuel system. Many automobiles cannot run ethanol for this reason. I would play it safe and avoid it.

+1

I would not run any ethanol unless absoluty necessary.

If you're in an area of the country where you have to use it, I would start planning on having the rubber seals and gaskets replaced.

Easy