F650GS(2001) 95RON question
 

Hello all,

I'm currently in Cairo and am a bit concerned about fuel grades here in Egypt and also in Sudan etc. So far, I have only been using 95RON unleaded fuel as per the heynes manual suggests... !

Will my 2001 F650GS run on anything less? 92/90 etc. In Sudan, there is no 95RON available.
Is there something I can do to the bike to enable it to take lower octane fuel?

Hope someone can help, I'm a bit confused by it!
Cheers,
James

no 95
 

Hi
long term use of unleaded fuel will kill the cat.
short term use will not.
you can use an octaine booster....if you can get it.. which I doubt you can where you are....
but its really not a problem - so dont worry about it.

just make sure that your air filter is clean and when you can get good gas put some in!

note: I've used all sorts of grades of fuel - mostly unleaded but I took out the cat. and now my bike will run on anything really with no probs!

I think you meant long term use of leaded fuel will kill the cat?

..opps
 

LOL - yep I sure did!
just checking that there is someone alive out there to read these posts!
Ta!

Hello, thanks for the info Lisa, I feel slightly reassured now! There doesn't seem to be much information on the interweb about F650's and fuel issues.. - I'm taking this as a good thing! I'll go for a test ride tomorrow and sample some Octane 92. Thanks again.

James in Cairo

the f650 can run on dingo piss...

using the North american fuel rating system, you can run on 87, 89, 91 or 94 (chevron), my 07 dakar usually gets fed the cheapest swill I can find, if the computer management is running fine, the bike can compensate for the lower octane by adjusting the spark advance.

Higher octane translates into the fuel exploding faster, meaning for really high revs you can utilize it, but on a thumper? Riding the poor girl over 6000 for long periods is just cruel...

Fuel milage and feeling for my dakar (with 77,000 on it) fully loaded, refill at 15 litres

87 octane -usually about 240mile/tank, feels normal
89 octane -usually about 220mile/tank, slightly quicker acceleration?
91 octane -usually about 200mile/tank, definitely crisper at throttle, but on a 600lbs load bike, its a matter of inches, not miles.

You should feel safe putting in the best you can find. If you do get into a lot of leaded fuel, and you are running OEM exhaust, this is a perfect excuse to finally bash that cat ceramic out, or else get a single sided (proper) can on that bike...

Thanks 463 for the good and happy news! I'm assuming my computer management is fine so it sounds like I have nothing to worry about. I'll be servicing the bike over the next few days so the air filter etc will be new as well. The only difference is that mine is the 2001 version but I think i'm going to have to stop worrying and get on with the trip! Good stuff, thanks both.

James.

I've used leaded fuel over the course of 1000km. That's 50000 km ago, and the bike is still fine. A BMW technician told me that once I'd run the cat on unleaded for 2 tanks, the lead will be cleaned out of the cat.

I've run the bike on as low as 80 octanes, probably even less... in Tajikistan's Pamir mountains, I believe they dilute it with water (or yak piss). No problems whatsoever.

The F650 does NOT have an anti-knocking sensor built in. On low octane you'll hear your a rattling noise from your engine if you're too keen with the gas. Just ease off the throttle then & you'll be fine.

Overall fuel consumption will depend a bit on altitude as well – in Bolivia's altiplano I noticed I get a higher mileage than in the lowlands. Sometimes up to 230 miles before the fuel light came on (still at least 60 miles left left).

Reprogram Fuel Injection?
 

My wife's 2001 F650GS was designed to run on premium (unleaded of course for the cat). Before our trip through Africa we took it to a dealer to change the computer programming to run on regular gas. There was a BMW service bulletin for this but I can't find it at the moment. I believe the system changed around 2005 (or whenever they went to dual plugs) so that the F650 could run on regular straight from the factory.

After the programming change we didn't have any trouble going through Egypt, Sudan and Ethiopia (where fuel was probably the lowest octane judging by the 45 gallon barrel it came from).

As mentioned above, ride carefully and listen for pre-detonation. Have a great trip!

Funny, I thought lower octane was more volatile, with higher octane necessary for high compression engines (to eliminate pre-detonation). For this reason, when you get pre-detonation you cure it by using higher octane gas.

If you tell me I'm wrong about this, my whole interlaced view of the universe will crumble and disintegrate, so please proceed gently.

Mark

Universe still OK!
 

Hi Mark,

You're right, the lower the octane the faster, more uncontrolled the burn. At higher revs there is less time between compression and spark ignition so a lower octane fuel won't ping as badly as at lower rpm. It should be noted that it needs to be higher revs and low load since higher loads equate to higher heat and therefore greater chance of pre-ignition.

The 2001 F650GS does not compensate for lower octane fuel as it doesn't have a knock sensor like the new F650GS twin or the R1200GS. That's why it needs to be reprogrammed if it originally came requiring premium. The R1150GS utilised a coding plug (looks like a relay under the seat) to accomplish the reprogramming whereas the F650 needs a BMW service centre to hook up their computer to do so.

Ekke, going by that then I should have had my 2001 f650gs connected to a computer for re-programming... I didn't.. I have been using 92 for the last few hundred miles and the bike seems happy at 3500-4000 ish revs cruising along but it's cutting out a lot at low refs.

I haven't even tried 90 octane or lower yet. I'm about to get on the boat to Sudan on Monday... Am I doomed!!?

I realise that all of the above is about the F650GS; to what extent would the advice given relate to the F800GS?

Doomed?
 

I don't believe you are doomed but realise that there may be some pinging. We went through that part of the world a little later and the temperatures weren't insanely hot (36 C), I hope you have the same luck as high heat and high load will make it worse.

In the section south of Wadi Halfa we got fuel out drums so I can't imagine it was high octane yet none of the bikes we were with had any trouble. That includes Audrey's F650GS, my R100GS, a Suzuki V-Strom and two Ducati Multistradas. The Ducatis especially I would have thought to be set to run on premium. Just enjoy the adventure!

No, this discussion doesn't apply to the new F800GS or the new F650GS Twin. Completely different engine management systems.