Misfire at around 5500 rpm after riding hard....

Funners

Funners

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Right heres the scene...
Whilst in Norway my Adv started misfiring at around 5500 rpm but only when it felt like it..mostly after it had been ridden hard or when under load up a steep hill, if you could get thru it it ran fine up to the red line but if you got stuck in it, you had to change down to get out of it...
Best I can describe it is like riding Flat slide carbs and whacking the throttle open too soon..
Back in the UK and at the 12000 service I mentioned this..
dealer checked everything, all coils OK, nothing untoward and it's been fine since.
Yesterday however it's started again....ride it hard and the "Hole" develops" it's very noticable, ease off for a bit and it's OK again....:nenau
the bike is an 07 Adv, with Remus headers and BOS can, it has run fine for a year with that combo on before this started.
plugs have been changed (made no difference) different air filter has been tried.
the FPC has been changed to the latest one

Any idea's ??:)
 
My 57 plate with 10500 miles does the same thing but to a lesser extent to that which you are discribing. It only happens when riding it hard, it will do it particularly if you have come off the throttle and then really give it some. I would discribe it as a 'mis'. I think its just a fuelling glitch, its at the point where there is a known flat spot.
I removed the 'cat' hoping that it would dissappear, but allthough it has improved the situation it hasnt gone.
 
Funners said:
....ride it hard and the "Hole" develops" it's very noticable, ease off for a bit and it's OK again....:nenau
Click to expand...

:ymca

Sorry dude, but I did have to chuckle at that one. My mind is obviously in the gutter (along with the rest of me). :thumb
 
if i was a gambler i would put my money on a bad coil , sometimes when they are tested they will read ok, find a buddy do a swap for a few days,[ohh what am i saying of course iam a gambler i bought a bmw.:
 
Most of these kind of faults on GS seem to be spark related: plug, coil, lead etc.

Two things normally make life harder for the spark to errr.. spark, one is big throttle openings under load as the density of the compressed gas is at it's highest, the other is high rev's if the ignition system is getting a bit flakey.

However, a weak mixture will also cause a misfire under load such as if for some reason the pump isn't fully performing causing the pressure in the injection system to drop. If it was an 1150 I'd suggest you change the fuel filter in case it's partially blocked, but of course there isn't an equivelent in the 1200.

Water in the tank can also cause a misfire

The fact that you seem to be able to ride 'through the hole' and out the other side is a bit odd if you were looking at an electrical issue and so I'd also consider the idea that you are already running lean as you have the non-stock exhaust on and there's something slightly amiss with the fuel pressure in the system that just tips the balance from time to time.

However, as I said at the beginning, most of these kind of faults on GS seem to be spark related: plug, coil, lead etc. ;)

As the other guys say, substitution is likely to be the only way you can track this down.
 
Open exhaust system, free flowing filter, high speed misfire ???

Do you know if your mixture is too lean at larger throttle openings?? My suspicion is that it might well be, and that you need to get it sorted before you do some physical engine damage.

High-speed detonation literally wrecks engines.

If it were my bike, I'd get a rolling-road dyno session done just to witness the power curve and mixture under load - not expensive (unlike full-on dyno tuning/mapping).
 
Pukmeister said:
Open exhaust system, free flowing filter, high speed misfire ???

Do you know if your mixture is too lean at larger throttle openings?? My suspicion is that it might well be, and that you need to get it sorted before you do some physical engine damage.

High-speed detonation literally wrecks engines.

If it were my bike, I'd get a rolling-road dyno session done just to witness the power curve and mixture under load - not expensive (unlike full-on dyno tuning/mapping).
Click to expand...
No mate...it's a std air filter ( I changed to a different one to make sure it wasnt blocked)
remus headers and BOS can with the road legal insert in, plugs are a nice coffee colour AND it ran with these bits on for a year before the symptoms started...;)

the other issue is the intermittent nature of it...bad fueling would show all the time where as this doesn't:thumb
 
I think the cold air entering the airbox may have something to do with it as you say it happened in Norway and also here now the weather is cold. I suspect the fuel system has a sensor for incoming air temp or pressure (and thus air density) as there is one on the side of the airbox

Perhaps the bikes fuelling under colder/denser air conditions is not as good as it could be, and if so then maybe a rolling-road tune with a power commander would be the only way to dial it out ?? Just a guess.:nenau
 
Interested that it first happened in Norway as I have been looking at going there. However reading several posts I see there is a very low speed limit and quite strong reinforcement. This somewhat puts me off as the distances are quite great and the thought of sitting at 55 mph all day is a bit of a turn off. What were your findings?
 
rodsharp said:
Interested that it first happened in Norway as I have been looking at going there. However reading several posts I see there is a very low speed limit and quite strong reinforcement. This somewhat puts me off as the distances are quite great and the thought of sitting at 55 mph all day is a bit of a turn off. What were your findings?
Click to expand...
That the Norwegian speed limits are policed very much like the UK ones.
Stick to the limit where it is posted, and in places where lots of revenue is likely to be made by lots of people speeding (long straights near built up areas), but out on the open road....

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Pukmeister said:
I think the cold air entering the airbox may have something to do with it as you say it happened in Norway and also here now the weather is cold. I suspect the fuel system has a sensor for incoming air temp or pressure (and thus air density) as there is one on the side of the airbox

Perhaps the bikes fuelling under colder/denser air conditions is not as good as it could be, and if so then maybe a rolling-road tune with a power commander would be the only way to dial it out ?? Just a guess.:nenau
Click to expand...

rodsharp said:
Interested that it first happened in Norway as I have been looking at going there. However reading several posts I see there is a very low speed limit and quite strong reinforcement. This somewhat puts me off as the distances are quite great and the thought of sitting at 55 mph all day is a bit of a turn off. What were your findings?
Click to expand...

AdamA said:
Ya think wrong. It was 30-35 degrees most of the time in Norway and the lowest we saw was 17degrees IIRC. ;)
Click to expand...

AdamA said:
That the Norwegian speed limits are policed very much like the UK ones.
Stick to the limit where it is posted, and in places where lots of revenue is likely to be made by lots of people speeding (long straights near built up areas), but out on the open road....

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/2uFWyffJCMw&hl=en_GB&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/2uFWyffJCMw&hl=en_GB&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>
Click to expand...

;) What he said.... Noway was fekkin BOILING.....the two weeks I had in the South of France were cooler...:cool:
 
I assumed you did Norway when it was a little less temperate.:blast

It can't be boiling though mate, thats reserved for Western Australia and the Gulf States (45 degrees centigrade). A bit warm morelike.

As for the misfire, I'm outta ideas matey apart from a 'hole' in your fuel map under certain load/throttle conditions.
 
:) Just as an update to this issue for those who may or may not be intersted...
The coils all checked out OK on the machine at BMW... but still the problem persisted, so I bit the bullet and purchased some replacement secondry coils...

guess what ??

job sorted, no misfire, no hole to fall into and an extra 2-3 mpg as well...:D

Thanks for all the sugestions;)
 
The secondary coils can rust quite badly and the steel cores delaminate. They appear rusty and expanded when you look at them. My original 2004 model 1200 did this, and my current 2008 model is going the same way.

Be sure to coat the outside of the new coils with a good thick coating of ACF50 or similar before fitting them and replacing the coil covers.:thumb
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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