1150 - running rough around 4.5k revs...

gabriel_gs

gabriel_gs

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Hi folks,

Did a bit of searching, but to be honest I didn't find much immediately and I'm at work and there was a fire drill and my finger hurt and.... :augie

Anyway...

My 1150GS is running really rough at about 4.5k revs - only really noticed it on the motorway in 5th and 6th gears (recently changed my commute, so could have been this way for a while) - when you try to open it up past 4.5k revs it's really reluctant - a bit 'surge-y' and kind of splutters through - you get some kicks of power, but it's really rough in general above 4.5k revs.

In lower gears and revs (actually probably just the lower revs being relevant) it runs just fine

Any thoughts? :nenau
 
Or might it just be a simple thing like a dodgy plug or the throttle bodies need balanced? :nenau
 
Spark plugs I think I can check - 'stick coils' could be the name of a Pop band for all I know.

I'll do a search - thanks chaps
 
Ok, so if I've researched this correctly...

- Run the engine to warm up
- disconnect lead the the secondary spark plug on one side, engine should run fine
- reconnect and then disconnect the lead to the secondary spark plug on the other side
- if engine stutters/runs rough then I've found my problem, ie a dodgy HT lead/Stick Coil

Is that right? :nenau
 
That's almost right. But it narrows it down to a faulty coil stick or spark plug so don't go replacing the coil stick (even though it's the most likely culprit) until you've checked out the plug. Either put a new plug in or swap them side to side - if the problem switches sides then it's the plug, if it doesn't it's the coil stick.
 
gabriel_gs said:
Ok, so if I've researched this correctly...

- Run the engine to warm up
- disconnect lead the the secondary spark plug on one side, engine should run fine
- reconnect and then disconnect the lead to the secondary spark plug on the other side
- if engine stutters/runs rough then I've found my problem, ie a dodgy HT lead/Stick Coil

Is that right? :nenau
Click to expand...

You pull off both lower spark plug caps. So it's only running on the main plugs.

If it's the coil caps (main plug caps) that are faulty it either won't run or start at all ( both have failed), or will run on one side ( one has failed).
 
+1 to Steptoe :thumb

I disconnected both secondary spark plugs and the bike would hardly start, so I guess one of the main plugs OR one of the caps is faulty?

Where do I go from here, chaps? What can I check next?
 
Wait!

Solved the mystery.

I unplugged both secondary spark plugs.

Then I unplugged the right side main spark plug. Bike started reluctantly, but started.

I then replugged it and unplugged the left side main spark plug

The bike wouldn't start.

SO, obviously the right side spark OR coil stick is duff...

Next, I switched the spark plugs right to left, left to right - same result when testing wiht one side plugged, then the other - so not the spark plugs then.

I then put the spark plugs back as they were and disconnected the coil sticks themselves and swapped them round - now the bike started with the right side spark plug attached and not the left

Soooooooo... I can deduce from that that the right side stick coil is buggered?

Sound about right?

(sorry if this is painfully obvious to everyone else, but I am learning as I go!)
 
Yikes - £60+

Sorry, we're talking about BMW... I shouldn't be surprised!

Thanks again for the help chaps! :beerjug:
 
And here's what it looked like when I took it out....

stick_coil1.jpg


stick_coil2.jpg
 
All done - bike running beautifully again.

Thanks again for the advice folks!
 
Actually, I lied.

It seemed to run better, but it might have been my imagination - I still now have the same problem - in all gears, really.

The general issue is that if I half-twist the throttle, the bike accelerates nice and smoothly, all fine.

If I give it any more than half-throttle or twist it to the stop, it's almost as if the power drops and the acceleration is really juddery/jerky.

I will check the stick coils again this weekend - what else can I check?

The spark pugs themselves? How would I do that?

Anything else to check?
 
Check the spark plugs by replacing them - they're not expensive. Spark plugs do fail - I had a primary plug go on my 1200 (after only about 3k miles) and the symptoms were similar to what you describe - OK on a light throttle but the harder you ask the engine to work the worse it runs.
 
Solved!

Was one of the spark plugs - dunno which one as I just replaced them all.

Now seems to be running like normal - no drop in power, pulling strong al lteh way!

Thanks Sproggy - the virtual cigar goes to you :thumb

Here's how they looked..

The upper plugs were white and powdery:

upper_1.jpg

upper_2.jpg


And the lower ones black and oily:

lower_1.jpg

lower_2.jpg



Either way, my bike's back running as it should.

:JB
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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