"Bogging down" at motorway speeds ??

[Bikerbrady]

My 2004 r1150 Gs adventure runs really smooth round town etc, acceleration etc at lower speeds is fine.

On the motorway accelerating form 70ish or so it bogs down, it does accelerate all be it in a not so smooth way, more hesitant but does get there. Very smooth holding the bike at 70, 80, etc its just the in between getting there thats not so good??

Its almost like intermittent fuel starvation.

Bikes booked in later in May for RGM to have a look at but just thought I'd throw it in to the forum. By the way Roy has just done the 24k service and the bike has never run so well its just this acceleration problem at higher speeds.

Any ideas as the bike generally runs bloody great

Biker

 

[cookie]

maybe a failing coil pack?

 

[harry]

Water in fuel gives these symptons too...

 

[Bikerbrady]

My bike went back to williams a week or two back under warranty as the drain hole in the fuel filler cap was blocked and water was getting into the fuel tank when I opened it to fill her up, they sorted the bike (apparantly?) when I took her in.

I too was thinking of the coil packs but at £53 quid each they are an expensive item to buy if they arent the problem.

I wonder if water is still in the system somewhere?

Biker

 

[Loiq]

would guess if it's been in once for similar fault chances are higher than average it'll be that again.

Hope they sort it nothing worse than expecting it to go and all it does is slow down... normally that happens just before a brown trouser moment

 

[littleredrooster]

My single-spark 1150 used to do this until I set the TPS voltage correctly. A low voltage makes it run weak.

 

[Bikerbrady]

Okay I now have a few ideas of what it may be

2004 1150gsa

Coils (I actually know where they are )
TPS voltage (what is that and where do you check it)
Lambda sensor (again what where)
Hall sensors (and again, what where)

I have no intention of tinkering myself but would like to know just to get a better understanding of my bike

Biker

 

[AlanAce1967]

Funny you should mention this but my bike did it this morning. A few weeks ago it did it coming home from work, i had done around 10 miles, was in 6th gear doing approx 80, went to accelerate and there was nothing there, the bike slowed down, if i came off the gas the bike slowed down quicker than usual, i put it down to a one off and possibly imagined as i was heading into a very stong headwind. But... did it again this morning, again after about 10 miles, dropped a couple of gears and opened and closed throttle and after 15 seconds seemed to clear itself and all was well again.
Only seems to do it when im travelling at a constant speed around 70-80. It seems as though there is no fuel getting through.

 

[Carl]

Funny you should mention this but my bike did it this morning. A few weeks ago it did it coming home from work, i had done around 10 miles, was in 6th gear doing approx 80, went to accelerate and there was nothing there, the bike slowed down, if i came off the gas the bike slowed down quicker than usual, i put it down to a one off and possibly imagined as i was heading into a very stong headwind. But... did it again this morning, again after about 10 miles, dropped a couple of gears and opened and closed throttle and after 15 seconds seemed to clear itself and all was well again.
Only seems to do it when im travelling at a constant speed around 70-80. It seems as though there is no fuel getting through.

I had the same symptoms... I was convinced it was fuel starvation and faffed around changing fuel filter amongst other things. All to no avail as it was the coils.

Bought 2 and got a slight discount good job really... replaced one, then a month later the other one packed up. Both looked fine with no visible corrosion.

 

[Bikerbrady]

Ive had a look at my coils this morning and they look absolutely fine but I know that means nothing. After you changed your coils did it stop the problem?

Biker

 

[cookie]

quick and dirty check for duff coil packs, courtesy of bmw agent workshop.


unplug the secondary coils and see if it runs better without them.

 

[DavidHale]

Slipping clutch?

 

[Bikerbrady]

Clutch is fine, its not slipping, pulls like a train!

 

[Bikerbrady]

SORTED, managed to get my hands on a couple of coils just to see if that was the problem, put the new ones in..............started the bike and I knew instantly, tickover at cold idle was much much better and much smoother, took her on the motorway and no more "bogging" down, I didnt realise just how bad the bike was (I thought it was okay) until I put new coils in.

The bike is now so smoooooth and no hesitation etc.

The bike even starts quicker from cold, a very happy chappy indeed

Biker