F650GS 800 engine cut out - SORTED

[rodrigoscs]

Hi,
It happened for a few times, while riding on motorway the engine starts cutting out like as if running out of fuel. Usually comes back to normal as I don't even need to let go the throttle, but once I had to start with the ignition which did straight away. It happened just once to cut out at slow speed in town.
I thought the problem could be the fuel pump, so ordered a replacement but it still doing it!
I'm a bit lost on where to look now...
In the last couple of weeks I changed the oil and filter, cleaned and reconditioned K&N air filter, it got new plugs a couple of months ago, just got new fuel pump, been using Redex fuel system cleaner...
Would a diagnostic toll help to find the issue reading the fault codes? (I got a mate with a dealer diagnostic tool and software)
Any ideas please?
Thanks

[Tonibe63]

Look on UKGSer, it will be on there (thumbs)

[Malc6552]

Could be the fuel pump controller or did you change that with the pump?

[royle100]

there is a petrol vacuum issue with 800gs tank, generally when weather is hot. Apparently there is a breather pipe that gets blocked. Guess you could try a run with fuel tank cap open and see if that's the issue?

[rodrigoscs]

I had the vacuum problem right after I bought the bike and the BMW dealer just removed the breather valve and never had an issue again (for 30K). This was located on the rear of the bike under the seat.
I only changed the pump, not the controller. I'm a bit reluctant to spend more money in parts without knowing for sure what's the cause, although I'm suspecting this will be the only way!!it's more than £100 new and £55 second hand from Motorworks.
I read about someone that bypass the fuel controller to resolve fueling issues, but was never specified what was the problem with it. Can a fuel controller cause this kind of problems?

[DaveCon]

Why are you running with a K&N filter? I think I would try a normal filter as it's easy to change. It could be buggering up the fuelling :huh:

[rodrigoscs]

Why are you running with a K&N filter? I think I would try a normal filter as it's easy to change. It could be buggering up the fuelling :huh:

I've been using this filter for the last two years at least and never had a problem. Including long rides to warm countries and long days offroad on dusty trails. Pretty sure the problem isn't here. Anyway, the filter is as new again and the problem persists.

[royle100]

If you don't figure it out try Mark Holden MC in Bromley 020-84644400. Independent BMW specialist

[OnHellas]

I had a similar problem with the fuel pump in hot weather. 35 degrees C plus, but only with 6 litres or less of fuel left. Full tank, no problem. The bike had done about 25,000 miles at that point.
The fuel pump controller is usually not an issue on the 800's. the fuel pump
Problem seems to be mainly on the earlier bikes. 08 and 09.
Another issue that I encountered last year that also felt as if the bike was running out of fuel was when the EWS antenna ring started to fail. Another 150 miles of stop start and the bike cried enough with the EWS fault code displayed on the instrument warning display. The bike had done 55,000 miles at this point.
It is easy to speculate and chuck out loads of red herrings, maybe you need to get the bike plugged in.
Bike now on 87,000 for the record. The last 32,000 with a sidecar. Fuel pump all OK.

[mjojom]

as said, check vacuum. once you have the issue, stop and poen the tank -listening for woosh - air being sucked in. or as suggested, try to ride her with tank open.
have you changed spark plugs recently?
to to be sure, cut out happening when under throttle, or when easing off the throttle?