Horizons Unlimited - The HUBB

Horizons Unlimited - The HUBB (http://www.horizonsunlimited.com/hubb/)
-   BMW Tech (http://www.horizonsunlimited.com/hubb/bmw-tech/)
-   -   total power failure f650 twin - stuck in khartoum (http://www.horizonsunlimited.com/hubb/bmw-tech/total-power-failure-f650-twin-50146)

dajg 8 May 2010 08:12

total power failure f650 twin - stuck in khartoum
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.


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

Bertrand 8 May 2010 12:38

If time/visas/money permist consider buying the 'Hex 911' dongle and getting it sent to you. It will interrogate your bike and tell you the real story. You will need either a notebook with a usb lead OR if you buy the bluetooth version, either noteboook and lead OR a mobile phone with bluetooth- the phone needs be JSR82 compliant- to run the Java application.
Software for phone testing and 911 available for customers to download from site.

I do not know your 650 but I have a F650Dakar single- here is the BMS-C reset procedure- it may be the same for yours
  1. -Under your seat, remove the BMS-C (silver box)
  2. - allow about an hour disconnected
  3. -reconnect BMS-C (careful not to bend any pins)
  4. -turn on ignition ONLY (NOT engine)
  5. slowly rotate throttle to max and slowly bring back to nothing
  6. ==> do this last bit twice
  7. Turn OFF ignition
  8. Allow a few seconds
  9. turn ON ignition and turn ON engine (without using throttle)
  10. allow bike to warm up on its own until fan kicks in
  11. turn off
This will have reset the idle on the bike
If you have time,
  • you might also want to check that your fuel tank fuel filter isn't clogged up.
  • Check spark plug for possible 'bridge' (burn out carbon bridging electrode)
  • or possibly shorting from HT lead onto frame somewhere- if its dark it helps to find this-
  • Spark plug cap could also be fried
  • Check fuel tank venting- i.e fuel is being replaced with air
  • add some octane booster toy your fuel tank (great for cleaning a multi fuel stove too!)
Sorry it isn't much but all I can suggest - good luck Dave

dave ett 8 May 2010 18:56

These bikes are very good at saving fuel by cutting the injectors on the over-run. This is partly what caused the stalling problem as I understand it.

Have you tried winding the tickover up? Use the throttle cable adjusters below the front brake lever to stop it from closing the throttle completely.

Has it lost performance overall - more than you might expect with lower octane fuel? Perhaps the injector(s) are clogged?

Still got a catalyser fitted? This may be bunged with if you've had leaded fuel in it.

Have you checked for fuel leaks around the injection system?

Checked all electrical plugs are properly seated and undamaged from falling off?

Let us know if you fix it or need some more help!

Tim Cullis 8 May 2010 19:48

Hi Dave

I don't think it's the low grade fuel or the cat.

I had a somewhat similar problem on my F650GS twin that was never properly resolved before the bike was handed back to BMW. The final straw was having the bike recovered on a trailer on the way to Poland.

Have a read of my thread on UKGSer. It wouldn't hurt to try disconnecting the side stand switch, it's simple to do.

Anyway, I've cross posted your problem in the F650/800GS forum.


Hypographamist 8 May 2010 20:23

Hi Dave

Long shot but I've had bad experiences with low octane fuel causing 'wiskers' across
plug electrodes. These are carbon build ups and they play havoc with your plugs
firing. Symptoms are you're running fine then miss fire starts and increases, you stop
and bike starts OK after a while as the plug has cooled down and the firing up of the engine blows the wisker off the electrodes. Off you go again and the process repeats.
I found that a long coast with closed throttle then just as the bike is at a standstill
open the throttle and maybe the whisker blows off.

Permanent cure is difficult whilst all you can get is rubbish petrol.

Maybe try opening the plug gaps see what happens - easy to do and worth trying..

Good luck..


Tim Cullis 9 May 2010 00:17

Here's a thread I came across on F800riders.org talking about cut outs.


In June of 2008, CIP CD11.2 was released. In this update, one of the things that was specifically addressed was a issue that resulted in a cutout situation on the K72 motorcycles - the F800GS and F650GS Twin. The cutout, unlike what has caused the issues with the S and ST revolved around the sidestand.

The sidestand on each motorcycle is alarmed so that when down, or rather when not up, the engine will not engage in fear of the rider zooming off with stand down and causing an accident. What was happening is that the side stand switch was returning an, "implausible" signal to the computer and thus shutting off the engine.
This seems like it could be related to the problems I had, and may be helpful to you. In my case the problem raised itself sometimes by cutting out when the first gear was selected, but as I noted in my thread on UKGSer could be overridden by high revs.

The problem also occured when the bike started normally, didn't object to being put into gear, but then kept stammering when riding plus general total cutouts.


Mickey D 9 May 2010 05:13


Originally Posted by Bertrand (Post 288147)
If you have time,
  • you might also want to check that your fuel tank fuel filter isn't clogged up.
  • Check spark plug for possible 'bridge' (burn out carbon bridging electrode)
  • or possibly shorting from HT lead onto frame somewhere- if its dark it helps to find this-
  • Spark plug cap could also be fried
  • Check fuel tank venting- i.e fuel is being replaced with air
  • add some octane booster toy your fuel tank (great for cleaning a multi fuel stove too!)
Sorry it isn't much but all I can suggest - good luck Dave

Great trouble shooting here! I like the fuel filter idea. Can it be accessed easily on your bike? Sand in fuel might have clogged it?

Dave, sounds like you've done a good job checking everything. Keep it up,
try to be scientific and keep track of your results as you go through systems. Otherwise you'll go crazy.

Question: How old is your battery?
As an X aircraft mechanic I always like to check simple and relatively cheap things first. Try hooking up a "known to be good" car battery to your bike.
See what happens. Check charging output if possible.

I don't know the F650/800's well but I know CANbus likes a HOT battery.
I've heard of bikes shutting down from just a low battery (dead cell).

You've got some good guys helping here, best of luck figuring out the problem(s). Remember, simple, cheap things first. Obvious things.
Now what have you overlooked? Think! :confused1:


dajg 9 May 2010 07:54

the battery was replaced (old one was fine at 18 months & 40000km but i figured it'd be too much trouble to replace in africa) at the 40k service.

while inspecting the bottom of the tank breather i noticed the cable to the side stand was frayed.. i will have a closer look at this.

gotta get back to the bike and start checking the list..

thanks guys, will keep you posted.

Tim Cullis 9 May 2010 23:05

If you are not already aware, you can access the online parts fiches for the F800GS at Max BMW Motorcycles

dajg 10 May 2010 08:52

thanks Tim,

i haven't yet bypassed the side stand sensor because the bike stalled during warm up while still in neutral. i thought if it was side stand, the bike would only be stalling whilst in gear.

i bypassed the fuel pump electronics (part 16147719844 s/s by 16147720778 on max bmw) as per suggestions from bmw munich but the bike ran much worse, even dropping to 800 rpm prior to stalling.

the spark plugs were replaced at the 40k service however i haven't checked them yet - these were suggested again this morning by bmw jo'burg, so i will pull the airbox out shortly and have a look at these and the leads etc.

the cat seems fine, there is plenty of pressure out the exhaust, also i think a clogged cat wouldn't be an intermittent fault.

i've tried running the bike with the fuel cap open, this has no effect. likewise with the breather disconnected.

with my multimeter the battery was reading about 13.05 volts with ignition off so i think the cells etc are fine. also the terminals etc are all tight.

munich suggested checking the throttle positioning sensor to see the resistance. there are three terminals in the sensor, however i read 0 ohms on all the combinations whilst moving the throttle. thus, i've ordered a new sensor via DHL.... will see if it arrives & whether it helps.

i bought a bottle of injection cleaner which i will run through later though i think if this is the problem it would take a while for the cleaner to do its job. i cannot buy benzine / petrol octane booster here. there is a possibility of finding diesel octane booster but i don't know if that would be close enough... munich reckon i can't rule out poor fuel as the sole fault until i run "quality" fuel.

if there are any travellers coming with a truck, a can of 90+ octane would be great... likewise any bikers with a bottle of octane booster or a diagnostic tool... feel free to drop by the blue nile sailing club.

thanks for the ideas guys. if you think of anything else, obvious or otherwise, please let me know. my number here is +249927634682.

Tim Cullis 10 May 2010 09:46

For the sake of a few minutes work, I'd check both the spark plugs and the side stand switch.

Another suggestion from UKGSer was that it might be the lambda probe. A quote from Wikipedia "When an internal combustion engine is under high load (e.g. wide open throttle), the output of the oxygen sensor is ignored, and the ECU automatically enriches the mixture to protect the engine, as misfires under load are much more likely to cause damage" which seems to tie in to your experiences.

Anyway, the suggestion is to try disconnecting it in the expectation that it would fall back to a default map (not sure this is the case...).

See 650 cutting out at low revs - ::. UKGSer.com .:: (post #31) for a similar problem/diagnosis.

My experience with trying to import parts into third world countries it is often cheaper--and certainly a lot quicker--to get a friend to fly in with a selection of 'sale or return' parts and a GS911. A quick check came up with return KLM flights at less than £500, lastminute.com at under £350 and a host of cheaper offers that might or might not exist when you drill down.

I would offer, but my passport is currently away being renewed. :) Anyway, ideally you need someone technical.


PS: now cross posted on F800riders.org

Pumbaa 10 May 2010 09:49

Might be worth trying to speak to Chris at Jungle junction in Nairobi too. He knows a lot about the BMW (having work for them for many years). He might be able to get something to you which might be hard to get otherwise...maybe via someone travelling north.

Unfortunately haven't got his details with me, but I'm sure its on the hubb somewhere...

dajg 10 May 2010 15:53

ok, today i changed the plugs and added plenty of injection cleaner. still no luck finding octane booster.

went for a ride. as usual from (relatively cold start in 44 degree C heat) the bike was ok (city traffic, plenty of gear & RPM changes) for 20km.

after the first occurance, every time i back of the throttle, the bike stalls. so, i was 20km from camp and the bike stalled about 15 times on the 20km return. no good.

the leads which are visible around the plugs... look fine.

i will disconnect the side stand switch and go for a test ride later this afternoon (after peak hour...).

i am trying to order a lambda sensor (still doing homework on this) and a throttle positioning sensor (and maybe some octane booster if it can be airfreighted).

anyone technical with a gs911 and a handy bmw dealer interested in going though the visa hassles for a trip to khartoum...?

thanks again guys.

Dodger 10 May 2010 17:12

Always look for the simple stuff ,check filter[s] .

Octane booster can be made from toluene paint thinner up to 25% by volume mixed with gasoline .
I doubt if low octane is your problem though .

Threewheelbonnie 10 May 2010 17:56

TPS may be inductive rather than resistive. If it is you'll only find the fault by swapping it, with service software or with an oscilloscope. Maybe a fellow owner can confirm?


All times are GMT +1. The time now is 10:15.