also posted on advrider
total power failure f650 twin - stuck in khartoum - ADVrider

hey guys, i'm currently stuck in khartoum, sudan. the last 100km was done in the back of a pickup. Its 43 degrees C, and zero alcohol, but i'm sure somehow it could be worse.

background:

the bike did its 40000km service in stuttgart, germany. it now has just under 51000km. egypt is ok with 92 octane. sudan is generally somewhere in the 80 octane range (price was 1.8 sudanese pounds per litre), however before my problem became severe i did buy some cheaper fuel (1.46 pounds per litre) which was possibly as low as 76 (stations are few and far between - there was no alternative and the attendants speak f/a english). after the problem became very irritating i tipped the bike over & drained the fuel and filled up with a jerry of new 80 something octane. problem still exists.

through australia i rode in 40 degree heat and the bike was fine. through iran i was buying leaded petrol of dubious quality. the bike was fine. likewise syria, jordan, india, cambodia etc.

after 400km in sudan, with high 30's ambient temperature, i dropped the bike in sand (fell over - using bald michelin anakee rear...). i doubt this affected anything but i'll give you all the info.

the problem:

the problem started at low revs (400km into sudan from the egypt-sudan ferry crossing) - coasting into a petrol station or whatever in neutral or with clutch. the engine totally cut out. i could deal with this - just meant restarting.

about 50km after the possibly lower octane fuel i was sitting on 95km in 6th around 3.7 l/100km and 3200 rpm and the engine cut out (total power loss - no throttle response).

the ignition was still on, all guages, no warning lights. i pulled the clutch, turned ignition off, lights off then ignition on and hit start, kept rolling, geared down and away i went. this was ok for maybe 50-100km.

the problem got steadily worse. it was happening every 2km or so for 30km until i stopped to think for a bit (the battery was having more trouble starting the bike again). i tried the refuel etc. as per below to no avail.

finally i figured it was occuring as i backed off the throttle i.e. behind a truck while i waited for an opportunity to overtake. thus after a couple hours fiddling in a servo and calls to germany, i took off and cranked up to 100km/k in 5th at 4000rpm. bike was fine for 27km then no-go. had troubles getting it from the side of the road going again from 1st.

eventually i decided to jack the revs up again, doing 100km/h in 3rd gear at 5000rpm. i managed about 60km but every time i backed off behind a truck or for pothles / train tracks etc i lost all power. zero throttle response.

the problem has continually become worse all through the rev range. i might have done a bit further in 2nd gear but would have been pointless. i put the bike on a truck to the campsite in khartoum (pretty secure - blue nile sailing club).

there are no big bikes here. the closest bmw dealer who might have a diagnosic computer is kenya (gotta get through ethiopia to get there so a truck isn't a good option).

so - as far as i can explain - running fine, then back off slightly on the throttle (i mean a couple hundred to a thousand revs) and there is total, instantaneous loss of throttle & engine failure. the power loss is not gradual nor is there any warning.

attempts to resolve:

1. emptied tank by tipping bike & filled with slightly better fuel (there is nothing over 80 something octane in sudan). did not resolve
2. checked the breather tube from the tank (starts under the right side rear fairing). its routed clear of the rear tyre and doesn't seem to be blocked.
3. disconnected same breather tube from outlet. did not resolve
4. called germany...
4a. they suggested resetting computer by holding positive & negative battery cables together, then starting the bike with no throttle and waiting for it to warm up. before the fan kicked in the engine stalled. so, did not resolve
4b. they suggested watching the rpm guage when problem occurs - if the needle went straight back to zero (before i pull the clutch) this would indicate the ignition timing sensor was faulty. however the rpm guage drops normally as the bike slows down in gear (then to zero when i pull the clutch)
5. filled the tank. nope
6. checked the air filter. was pretty clean - i cleaned and reoiled in luxor 1000km ago. its a foam filter but i have a new paper one to try but i think problem is fuel delivery so haven't changed it yet.

i am aware of the common f800 stalling problem however this has only ever affected me once or twice before a fill up, and only maybe 7-8 times in the last 35000km. the symptoms aren't the same now.

i don't think the problem is:
- fuel quality
- ambient air temperature
- air filter
- any sand where it shouldn't be from having fallen over
- normal stalling issue common to these bikes

anyone had the same problem? anyone suggest a possible solution?

the import duties are likely to be in the 100's of % i.e. if i need a $1000 fuel injection system, with delivery is likely to be close on $3500... so i don't want to order anything as a maybe...

i'll be back online at least once a day until i solve this. if you want more info just post & i'll add it on.

thanks in advance
dave