Misfire under load

[The Grey One]

Just before I put my 1150 GS (2003 twin spark) away for the winter she developed a misfire. It occurs under load ie. when going for an overtake and allows only illegal,rather than silly, speeds.

Before certain members jump in can I say I have checked the "font of all wisdom" and done a search of threads in this section. That's not to say that the topic has not been covered, just that I have tried and failed to find it!

The local BMW dealer is not to be trusted with a pushbike and in any case I actually like to work on the bike myself. I have a download of a BMW workshop manual but it appears only to cover the single spark version.

I have time until spring to sort it out-once the season begins I need to be out on the bike, hard I know, but I have to ride our alpine roads often in the summer-it's my job you know!

I had a quick look at the stick coils and both show signs of corrosion, plugs look fine and are a good colour. I have been running with the Steptoe link in,but removing the link made no difference. I have a Remus can and Y piece that was fitted by the dealers before I took delivery of the bike in March 2003. The cat. has only been fitted 3 times and then for one day at a time- emissions checks are part of the MOT test equivalent here. Lambda sensor is fitted to Y piece.

So, oh wise ones-and the dummies amongst you - any suggestions? Does the corrosion on the stick coils (are there only two?) point to a problem? Anything else I can check now? Any parts I might need are best sourced in the UK, most bike parts here obviously come in diamond studded boxes to judge from the prices quoted.

One of the slight problems is that given our winter and the fact that our motorcycle garage is sealed up for it's duration I can't test run the bike again until mid march at the earliest-later if we still have snow then.

All suggestion gratefully received - well almost all. I have seen some of the replies people put on here!

John

 

[cookie]

the secondary coils would be my first suspects. if you can tell which pot is misfiring, you could swap them around to identify the culprit.

 

[Fanum]

the secondary coils would be my first suspects. if you can tell which pot is misfiring, you could swap them around to identify the culprit.

Definitely.

Are yours the older version (with black caps) or the later, more stable ones (with a large chunk of grey on the outside ends) ?

If the black ones , and the corrosion, I'd bet your left testicle they're the problem.

If you can meet up with someone with another 1150 TS, swap the coilsticks around to prove it......you dont need any special tools other than a pairt of flat blade screwdrivers to lever them out (or the plastic thingy that came with the tool kit that everyone has lost because it wasnt obvious what it was )

Haven't bought one for a while, but the coil sticks are around £60 each.

 

[The Grey One]

Makes my eyes water

Definitely.

Are yours the older version (with black caps) or the later, more stable ones (with a large chunk of grey on the outside ends) ?

If the black ones , and the corrosion, I'd bet your left testicle they're the problem.

If you can meet up with someone with another 1150 TS, swap the coilsticks around to prove it......you dont need any special tools other than a pairt of flat blade screwdrivers to lever them out (or the plastic thingy that came with the tool kit that everyone has lost because it wasnt obvious what it was )

Haven't bought one for a while, but the coil sticks are around £60 each.

Thanks for the reply BUT...
Even at my age I value my tackle so no bets on that area please! Strangely there aren't many local GSs, they appear to favour cruisers-with all these great roads why would you choose one? I doubt I will ever understand the Austrians. Anyway as I said I can't road test the thing until the spring. The corrosion is clearly visible and the casing appears to be slightly swollen. I expect I shall have to order a pair (they are the black variety) but it would be nice to know I am on the right track. Also it's bloody cold in the bike garage so I don't fancy spending too much time there just staring at the thing! Some pointer would be very much appreciated.

John

 

[cookie]

and the casing appears to be slightly swollen

another big clue that they are toast.

 

[Fanum]

another big clue that they are toast.

Yep, I'd almost bet my OWN left testicle on it now

It'll probably look a little like this underneath the casing

I strongly suspect that the coil pack from any twin spark 1150 will work.....I even ended up riding back from Morocco with one from a 3 series car fitted (the lead was three feet too long, but the coil worked fine to get me home....unlike the bike version, the car one is a one piece moulded unit integral with the lead itselfso I couldnt shorten it)


I don't think anyone has found a cheaper 'alternative fit' coil pack, although rumour had it that those from a Renault Megane would fit

 

[The Grey One]

Yep, I'd almost bet my OWN left testicle on it now

It'll probably look a little like this underneath the casing

I strongly suspect that the coil pack from any twin spark 1150 will work.....I even ended up riding back from Morocco with one from a 3 series car fitted (the lead was three feet too long, but the coil worked fine to get me home....unlike the bike version, the car one is a one piece moulded unit integral with the lead itselfso I couldnt shorten it)


I don't think anyone has found a cheaper 'alternative fit' coil pack, although rumour had it that those from a Renault Megane would fit

Thanks for that, I suspect you are right about the coils, I will get on to finding a suitable supplier. I can get them delivered to a UK address and then taken to Utrecht with our bike show stuff. Amazing show by the way, about 3 times the size of the NEC show but the hours are a killer for us poor exhibitors, 10am to 10pm for the first two days. - My wife will be driving there from England and I am bringing a load from here. Hopefully my Ohlins rear shock will be back from re building by then- pissed pre load fluid over the road-but that's another story.

Thanks again for the help

John