Hi,

My route isn't 100% confirmed yet, but my next trip might take me through some Central Asian states, including Tajikistan. From what I've heard Tajikistan only has very low quality fuel. Even worse (for my F650): it's likely to be unleaded all the way.

Solution would be to get a Remus or Scorpion exhaust. But the question is: is this enough for a modification? Would the Remus/Scoprion, or the low octane fuel upset the fuel injection anyway?

Last thing about injection systems: Does ambient temperature/altitude have an effect on the mileage at all? (Apart from injection systems giving more power in altitude, compared to carburetors)

Thanks
Bjorn

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I've run a K75 (EFI) on av gas - that is about 10 times the lead of leaded gas. For over 1,000km (600 miles) no damage, in fact I could not pick the difference in performance.

The EFI should give you better economy than a carby over varied conditions - as the carby does not have the sensors to vary its fuel usage that the EFI has.

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The low octane fuel may lead to 'pinging' ... (I'm assuming your bike does not have a 'knock sensor' .. the R12GSes have .. but I don't think yours does)

One way to counter this is to retard the timing.

Another way is not to operate the engine at low rpm with large throttle openings.

This has every thing to do with spark timing and compression ratio .. nothing to do with the fuel injection/carby.

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Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S

My F650 has been fed all sorts of crap fuel - from dirty 84 octane, to sweet 98 Argentina, and even 'Brasilahol' which was like petrol with added paint thinner.

Leaded fuel will clog up the catalyzer which stops it from cleaning the exhaust gas, the bike will run fine. I had the standard exhaust for 75000 miles with no problem, although it now has an extremely offensive straight through pipe as I got bored with the 'standard noise'. :-)

Bad fuel at altitude will make it ping a bit but all you have to do is be gentle with the throttle. The F650 does not have a knock sensor, the EFI has a smaller brain.

There's a noticable loss of power that starts around 3500 metres altitude but thats about all - its a very forgiving engine. I get around 22km per litre.

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This is how I'm getting around the problem, it works really well and it's pretty cheap as well, if you had posted a few months ago I had a spare but it's gone to a good home now.

Thanks for all your replies. One question though: What is a "knock sensor", and is this something rather important for high altitude/low octane?
I've read of a few 1200GS bikers who did Tajikistan (though they all had a Remus fitted because of the kat)

Juddadread -
I've seen you are using "Mr Funnel". How would you rate it so far (on your page you hadn't tested it in "low-octane-land" yet...)?

Cheers
Bjorn

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I love the Mr. Funnel, tip for you when you’re in the 'Stans' fill up a small jerry can and then fill your bike from that.

1. the petrol nozzle might not fit your bikes filler hole.
2. they only dump out the fuel in whole litres, so put 5 litres in the jerry fill the bike from that using the funnel and then refill the jerry as needed.

It will stop you getting splashed and maybe save your eyesight if it overspills like poor Ewan when he got it in the face.

Chris form MotoCross Africa also got one on my recommendation, and he also loves it. For the cost (£9) vs the expense of getting your bike fixed you know it makes sense.

Lee

When I was in the stans I found the petrol a bit variable, from 76 Oct max (Uzbekistan) to 96 Octane, leaded or unleaded and cheaper than water in Turkmenistan.
Rather than fill a jerry can then the bike I just asked for what I thought I needed and had an old drinks bottle to hand to swap over. If you go under and can fit more in just gesture to the attendant by holding up 1 or more fingers, they will get it. If you are fascinated by the site of all this exotic petrol going into your tank then jam the nozzle in, watch it carefully with your head a foot away and then you might get some in your eye. How somebody can get fuel in their eye ONCE like this is puzzling. To do it twice is just plain stupid.....

I haven't seen the mr funnel - is this for filtering fuel as it goes in? I used some ladies tights over the nozzle which worked pretty well. Couldn't wear them afterwards though. Avoid fishnets.

Your bike will probably run about fine with whatever you put in it, the main effect of poor fuel is on the inside of the engine. I would recommend that after a decent size trip through the stans or anywhere for that matter you should rebuild your top end (decoke, valve job). These jobs CAN be done perfectly well by an amateur in their living room - and will give (did for me anyway) a greater understanding of, and empathy with, your engine. Keep an eye on your compression to avoid doing this late (by the time I had limped back to Moscow from my collision in Kazakhstan Compression was 2.8:1 on one cylinder..).

While your on the road don't worry about it too much, you get what you get, that is all you get and it has to work. Take lots of spare fuel filters.

Enjoy, enjoy and enjoy. The stans are ace.

Mr Funnel - is a filter ... in a funnel .. removes water from fuel .. and dirt.


A knock sensor - an electronic gizzmo .. basicly a tuning fork .. has an output proportional to the amount of 'pinging' the engine has .. used by elctronics to advance/retard the spark timing to obtain maximum performance from the fuel being used with the engine in its present dirty (interior) state.

As for filling the bike when they only supply a certain amount of fuel .. ware your helmet, with the shield down .. one eye is worth much more than 10 hats!

Damage to engine? Keep an eye on your exhaust valve clearence! If you have any difficulty starting the bike when cold - check the exhaust valve clearence ... today.

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Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S

I understand the leaded fuel won't do the injection any harm, and the engine should be fine with it. As for low octane: I think we'll take some Octane booster with us (1-2l should be enough to get us through the worst fuel in Tajikistan/Pamir Mountains).

What if we leave the original (F650 Dakar) exhausts on? They've got a katalysator. Leaded fuel will jam up the kat. Now: does this affect the bike's performance in any way? Or could I just leave the kat exhaust on, not worry about a jammed up kat and do the ride. Later (if necessary) replace the exhaust later upon my return to the UK and "world of MOT"?

Bjorn

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Have another read of Happy Hacker's post above for his answer.

Suggestions:
1. Run the existing exhaust, possibly destroy the Cat (depending on how much leaded fuel goes through it) and get another one from ebay when you return here for an MOT test.

2. Do as 1 but in reverse - fit a second hand exhaust now and keep yours' for "best".

3. Fit an after-market that does not have a Cat and keep the OEM for "best".

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Dave

That's the first time I've seen Mr Funnel. Looks great. Which size would you recommend. And would you use them at the fuel stations as well or always out of a jerry can first?

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