Rough running at 4000/4500 rpm. "nothing wrong, sir"

[solidstate100]

Hmmm. Had the bike for three weeks now. Only had one BMW assist recovery so far so all's fine there then!

BUT even tho its just had an annual service at 15,000 mls and I specifically mentioned the rough running thing to the dealer (Bahnstormer), its still doing it, even tho as I say they say there is nothing wrong. Apparently it was road tested.

Is this normal at this rev range? Its almost like its misfiring (but not quite) sounds "ragged" at constant throttle and under throttle load and to my mind it definatly hesitates and feels like there is less power, especially when passing on the motorway etc. Which is a pain, cos those legal speeds are at the same rev range...

Once abve about 4500 rpm alls well gain.

06 GS, with Remus headers and BMW Akra exhaust, baffle out. Could that be something to do with it?

Thoughts?

Cheers all!

 

[John Armstrong]

06 GS, with Remus headers and BMW Akra exhaust, baffle out. Could that be something to do with it?

Thoughts?

Tried it without all that equipment that BM didn't know you were going to fit on their carefully set up bike?

Or taken it to a dyno to see if there's any fuelling issues?

 

[solidstate100]

Hi John

No - bought the bike with the exhaust (BMW approved, mind!) etc already fitted - by the dealer at purchase. And as I say it has been serviced by them subsequently, and brought to their attention. I havent thought about the dyno thing yet - its still under warranty and I want to investigate dealer options first before incurring extra cost.

I think what I was trying to find out is if there is any endemic issue like this - you know, "they all do that" etc. Also (tho I cant find it now) I seem to recollect someting about a software update for this

 

[solidback]

Try it with the baffle in. I have the same setup and find that the bike is much better with the baffle in place.

 

[John Armstrong]

IIRC the dyno charts show a steep increase in power above that 5000 ish rpm, so maybe your combination of extras, and how the bike is set up, is causing the engine not to be too happy.

Putting the baffle in might help, and it'll reduce one variable as well. Might be worthwhile trying to ride another GS with a simialr setup to see how it feels.

When I had a 1200GS IIRC it felt less smooth at about 75 mph in top gear, very usefull for guesstimating what speed you were doing on UK motorways. Is that about the same for yours?

 

[turbine_2]

I know with mine it's down to the spark plug caps, but then I've got an 1150 rather than a 1200 so it may be something completely different.

 

[Philj179]

Hi

Had something similar recently. Under load or agrresive 'power on' the engine would mis-fire / stutter but only when warmed up. Turned out to be a broken spark plug !. When the plug warmed up it was arcing inside the plug istself. Took ages to find. Hope this helps.

 

[solidstate100]

Hi Guys, thanks for all you replies so far - very helpful.

It does do it only when warmed up, and it does do it at 75 ish is well. Will start with sticking the baffle back in this weekend and start from there. Interesting about the spark plug thing tho as my gut feeling (im an ex mechanic) was tending me to think it was something possibly electrical that was beginning to "break down" under load.

As far as I am aware I dont think plugs have yet been changed (IIRC it seems they are good for 24k before changing, which to my mechanical sesitivities/mind seems an insane length of time) so that I think will be swap no 2....

Any more thoughts, keep em coming

 

[Andrew Lodge]

Search around the dealers for a similar one, pretend you might buy it and get a test ride, see if it the same as yours?

Maybe they do "all do that Sir"

 

[GSmonkey]

There is a flatspot around that rpm, which is actually made better with Remus headers. I too have the full system (with Remus can) and have put the baffle back in as I believe it gives a better response. Worth a try.

 

[brianmaslen]

Have you always had the problem or just started? I had exactly the same thing with my 1200GS and turned out to be spark plugs.They changed the coil initially, think there is one for each plug possibly, then settled on plugs and been perfect since.