Sudden power loss issue.

[harry the cat]

Has anyone experienced sudden power loss on the 800gs coupled with stalling issues. I've had this problem for a year now. Its happened about half a dozen times. It is intermittent, annoying, and potentially dangerous. Happened again today. 80 plus mph, fast lane of the M1, bike just suddenly lost power. On go the hazards, pray and pick a gap. Once on the hard shoulder the engine is still running but if you try to pull away it loses power again. Common factors are:

1. Its usually warm (or hot). Temperatures from low 20's to high 30's. Doesn't happen when the temperature is cold.
2. Its usually when the tank is low. Generally 180 miles plus although one it happened just 100 miles in.
3. Generally the only 'cure' is to limp using clutch and repeated starting of the bike to the nearest fuel station and fill up. Having said that it has on one occasion burst back into life and run perfectly for 15 or so miles before starting again.
4. It doesn't show up any faults on the dealers diagnostics.
5. There is always fuel left.

It would appear not to be:

a. A vacuum in the tanks caused by a blocked breather. No sign of vacuum and valve dismantled/checked.
b. Coil problem (changed).
c. Plug problem (changed)
d. Problem with the small breather pipes that run from the back of the air box which were perished and have been changed.
e. Crap in the tank or problem with fuel filter. Inspected.

Bikes recently had a 42k service and all updates done. Dealers are scratching their heads a bit although I have no issues with their effort. Thinking along the lines of sensor issues at present?

 

[Colban]

Have a read up on fuel pump problems.
They can stop/start intermittently.

 

[Bury_Dave]

Me too

Funny, I've had exactly the same problem today for the first time on my 16,000 mile F800.

Out with the misses on the back and an indicated 37 miles left in the tank. (I've been down to 10 miles left before ). Going downhill and the bike cut out then back on again. A few hundred yards further along , going uphill now, the bike cuts out and we stop. Missus dismounts and I open the filler cap and can hear fuel sloshing about - albeit not much. I try to re-start , successfully. We then spend the next 10 miles heading home with intermittent cutting out, several on the move re-starts and a couple of stops to bounce the bike.

Made it home (no filling stations en route ), drop wife off and go get fuel. Stalled once more pulling out of a junction . Nearly serious !

Did a couple of miles and everything seems ok - for now. Very odd indeed ......

 

[JayC]

Whilst it doesn't shine any light for you guys , reading this thread makes me feel glad to have got rid of my F8.

 

[Bury_Dave]

I hardly think one slight problem after 16,000 miles would be a reason to bin a bike especially if I was low on fuel ........ Do you drop your friends or get divorced as easily and for such petty reasons ? Or change your car ?

Shit happens. It's still a great bike in my view

 

[JayC]

I hardly think one slight problem after 16,000 miles would be a reason to bin a bike especially if I was low on fuel ........ Do you drop your friends or get divorced as easily and for such petty reasons ? Or change your car ?

Shit happens. It's still a great bike in my view

OP said "It is intermittent, annoying, and potentially dangerous".

You say it's a "slight problem" of "stalling coming out of a junction" , yep , sounds pretty petty.

I don't tolerate potentially life threatening situations that strike 'suddenly' and so yes , I'd drop the friend, get the divorce (though I'd have to be married first) and bin the car if they did the same.

Furthermore, it's so petty even the mechanics are scratching their heads.

 

[vaclove]

Got similar issue

Got similar issue last year during my Eurotrip. Bike started cutting off during hot weather. Also when the fuel was low.
German dealer who did the diagnostics claimed the it was because engine was overheating as there was something (old leaf or so) stuck in the fan. As the engine got overheated, then computer switched it off.

There were however holes in this theory as the engine temp on the board computer was totally fine. and I assume the cooling liquid won't boil off at once even the fan was not working.

Computer got reseted and I did not have the problem since (wasn't in such hot weather nor with very empty tank).

Try to check there is nothing stuck in the fan.

It will be very valuable for the F800 community if you could figure out what the problem is. Keep us posted.


P.S. Don't bin the bike.

 

[MikeMike]

When it does it, have you tried bypassing the fuel pump controller?

 

[harry the cat]

Ta.

Thanks for the responses to date, well most of them anyway.

Vaclove, its not the fan. Tried that, should have mentioned it. Still kicks in when the bike is left on stand with the engine running. Feels to turn freely. No temperature warnings.

Colban and Mike/Mike. I'll research the fuel pump and FPC side of things. I'm told there's a 40 page thread on adventure rider about the same issue.

I would be loathe to part with this bike. The F800gs is a great bike IMO and I don't think there's anything out there that is problem free. Not really a consideration at this point unless I can't resolve this issue.

Having said that the feeling that the bike might just decide to lose power at the wrong time (again) is a bit disconcerting.

 

[JohnnyBoxer]

Just swap bikes with the missus

))

 

[StumpyFingers]

I have not had it happen to me but it sounds like a common fault on the Africa twin.
The fuel pump fails. The bike runs fine when full and fuel weight can push the required volume through the pipes.


Sent from my iPad using Tapatalk HD

 

[Magnet]

Just swap bikes with the missus

))

No bloody chance!!!

 

[MikeMike]

See if your local dealer has an old duff fuel pump controller that they will give you instead of tossing it in the bin. You can easily rig up your own bypass cable from it with some scrap wire. It is not a bad idea to have one of these on your bike anyways. You can then try it out the next time the problem happens. Slogging through 40 pages on the ADV forum will probably take you longer than actually going to your dealer, getting an old duff part from them, and rigging up the bypass cable! Though it won't be as entertaining.

 

[Bury_Dave]

Did a couple of hundred miles today with missus on back and no problems at all so she can't be causing it Looks like it was low fuel related

 

[Micky]

Thanks for the responses to date ......

........ Having said that the feeling that the bike might just decide to lose power at the wrong time (again) is a bit disconcerting.

D'ya want to borrow my G650Xcountry for Wunderbar Deutschland next week Tony?

It's as quick as your 800

 

[harry the cat]

JB - The only time I got on the new shiny black 800 was when SWMBO was laid up after an operation. Then I was told to go and give it some exercise. An experience never to be repeated I suspect. I know my place

Micky - Kind offer. Must be fast to carry that weight at the speed it does. Still the new period of austerity will sort that eh?

Some interesting stuff on Adventure Rider. Appears the favourite 3 culprits in order of popularity are the fuel pump, the FPC and the fuel pressure sensor. None of these seem to trigger the diagnostics on their way to failure necessarily and all can present in the same way, warm day, low fuel etc.

Fuel bits bingo?

 

[stephen.stallebrass]

I've had EXACTLY the same problem... My dealer couldn't figure it out either. It did it on my current trip when in Germany, great I thought, they're bound to know, but they had no clue either. They changed the plugs but nope, next day same thing. I did make it to Mongolia and Siberia so it's not a show stopper, it's just fecking annoying. I'm convinced it's a FP/FPC issue too. Worst time it dome it was in Istanbul rush hour! A high ambient air temp is deffo an exacerbating factor!

Do let me know if you figure it out. Goodluck.

 

[harry the cat]

New bits

After some discussion with the wise men at Rainbow I have a 2nd hand pump on order from Sherlock's and a new FPC. Hopefully they'll arrive today and I'll swop them over before Sundays's excursion to Germany with Micky and co.

I suppose I should do them individually but if it cures the problem I'm not too bothered which bit it was.

Of course the other issue is the temperature has taken a dip and unless it picks up again I may not know for sure whether it's cured until next year seeing as it went from late September last year to this May without problems

 

[stephen.stallebrass]

After some discussion with the wise men at Rainbow I have a 2nd hand pump on order from Sherlock's and a new FPC. Hopefully they'll arrive today and I'll swop them over before Sundays's excursion to Germany with Micky and co.

I suppose I should do them individually but if it cures the problem I'm not too bothered which bit it was.

Of course the other issue is the temperature has taken a dip and unless it picks up again I may not know for sure whether it's cured until next year seeing as it went from late September last year to this May without problems

I'm currently in Munich and it's pissing it down!

I look forward to hearing if it fixes the issue. I'v seen a FP & FPC on fleabay in the past and toyed with getting them and trying it myself.

Good luck and keep us posted.

 

[MikeMike]

Keep the duff FPC and gut it so you can make a bypass spare that simply connects without having to run a longer lead to the battery, keep it in your tool kit.