A peculiar misfire

[Andre1150]

Well, it appears I can't delete what was a draft, ok. So I have this peculiar misfire that comes and goes on my 2004 1150RT with 89k.  It's been doing this on and off over the last year, now more so that I've started riding it more and noticing when it happens. It always happens at idle, whether warm or cold, starting up or after a long day of riding.  It only seems to happen at idle and when I'm waiting at a light or while the bike is stationary.  I don't seem to have this issue when I'm accelerating hard, or cruising along at highway speed. Nothing noticeable. However, when I'm idling at a light for a few minutes, the engine is humming along, and WHAM a misfire that wants to jerk the bike out from your hands. Then back to purring along, for a few more seconds, and then another heavy misfire. And the reason I say heavy is because it feels like the bike wants to move right or left when one cylinder doesn't fire and the momentum of the other piston isn't counterbalanced by an explosion on the other side.  Sometimes at a light, this doesn't happen though so it's very inconsistent.

I have not balanced the throttle bodies yet and nothing seems to show up on my GS911 either.  I've run a can of Seafoam through the gas  and checked the air intakes and airbox for leaks. Everything looks fine. Thoughts.

[dirtrider]

3 hours ago, Andre1150 said:

This issue comes and goes, happens often for a time, then goes away for a few days, then back again, more frequently now than before, But only during idle or with slight gas while waiting at a light, or slowing to a stop. A heavy misfire, feels like the bike jerks hard, then goes back to a smooth idle for another few minutes and then one or two heavy misfires and back to a smooth idle. Every time I'm at a light. The motor runs smooth on hard acceleration, long trips, and everything else, just when warming up, or after a few hours of riding when I'm idling, I get a heavy misfire that wants to jerk the handlebars out of my hands. Ive thought about balancing the carbs, feels like either too rich or too lean, but don't know where to begin..  thoughts?

Morning Andre1150

 

No carbs (carburetors) as you motorcycle has electronic fuel injection.

 

We need more info on your motorcycle, is it a single spark engine or a twin spark engine? (2 spark plugs or 4 spark plugs)?

 

What country are you in?

 

Any modifications to your engine or to the fueling control system?  

 

I have some thoughts or ideas on your problem but some are dependent on if you have a single spark or twin spark engine. 

 

[Andre1150]

4 hours ago, dirtrider said:

Morning Andre1150

 

No carbs (carburetors) as you motorcycle has electronic fuel injection.

 

We need more info on your motorcycle, is it a single spark engine or a twin spark engine? (2 spark plugs or 4 spark plugs)?

 

What country are you in?

 

Any modifications to your engine or to the fueling control system?  

 

I have some thoughts or ideas on your problem but some are dependent on if you have a single spark or twin spark engine. 

 

Morning DirtRider.  Sorry about the rambling post earlier (hadn't had my coffee yet) .. the 1150 is a twin spark no mods to the fuel control system.  I replaced the spark plugs a while ago, which didn't impact the issue either -- and I did think that maybe one of the spark plugs isn't firing (burning all the fuel) but a full swap of the plugs didn't seem to resolve the issue.  I should pull the plugs to see what color/etc and test them to see if I can figure out which cylinder is causing the issue.

[dirtrider]

24 minutes ago, Andre1150 said:

Morning DirtRider.  Sorry about the rambling post earlier (hadn't had my coffee yet) .. the 1150 is a twin spark no mods to the fuel control system.  I replaced the spark plugs a while ago, which didn't impact the issue either -- and I did think that maybe one of the spark plugs isn't firing (burning all the fuel) but a full swap of the plugs didn't seem to resolve the issue.  I should pull the plugs to see what color/etc and test them to see if I can figure out which cylinder is causing the issue.

Afternoon Andre1150

 

There are number of things that can effect the engine idle quality on the BMW 1150 twin spark but before chasing other things lets  start with a common problem on the 1150 twin spark.

 

That is with the o2 sensor wire pigtail routing in relation the R/H lower spark plug wire.

 

There was a BMW service bulletin on the 1150 twin spark to re-route the o2 sensor wire away from the right hand side spark plug wire, the plug wire can induce a voltage spike in the o2 sensor circuit & cause a severe miss at idle.  

 

Check your messages on this site as I sent you some re-routing info. 

 

It's kind of difficult to explain the re-routing procedure so just follow it best that you can -- just keep in mind that do not allow the o2 sensor wire to route along, or close to, the R/H lower spark plug wire & it should be fine.  

 

Also make darn sure that the R/H throttle body cam is not contacting or cutting into the R/H lower spark plug wire at closed throttle. 

 

Do this first then ride the motorcycle for a while, if the problem goes away then all is good, if the problem is still there then post back & we will address other possibilities. 

[Andre1150]

the little "miss" is back after rerouting the wires, it went away for a few weeks, then the clutch and slave failed on me in heavy Los Angeles traffic and I was nearly run over before limping home in 2nd gear. So, it's been sitting for a while as I got the new clutch in and replaced the slave cylinder, etc. ( which also lead to another problem that I'll outline in a different thread)

So, the miss is back, and not in a good way, although is is far more dependent on the engine being warmed up than before. ie. i can ride all day and not hear it, then i'm at a light and the engine misses so badly it nearly jerks the handlebars out of my hands, and then runs again for a few minutes, then misses again, and so on. Then after riding home, it misses again when I'm parking. The next day, no miss till the bike is fully warmed up and I've gone a few miles. However, now I have a brake issue and this issue is on the back burner.

[dirtrider]

10 hours ago, Andre1150 said:

the little "miss" is back after rerouting the wires, it went away for a few weeks, then the clutch and slave failed on me in heavy Los Angeles traffic and I was nearly run over before limping home in 2nd gear. So, it's been sitting for a while as I got the new clutch in and replaced the slave cylinder, etc. ( which also lead to another problem that I'll outline in a different thread)

So, the miss is back, and not in a good way, although is is far more dependent on the engine being warmed up than before. ie. i can ride all day and not hear it, then i'm at a light and the engine misses so badly it nearly jerks the handlebars out of my hands, and then runs again for a few minutes, then misses again, and so on. Then after riding home, it misses again when I'm parking. The next day, no miss till the bike is fully warmed up and I've gone a few miles. However, now I have a brake issue and this issue is on the back burner.

Morning Andre1150

 

Just not enough info to tell you conclusively what is happening--

 

Might be your o2 sensor acting up,  or a dripping fuel injector, or a stick coil issue, or a lower spark plug cutting out, or ?????

 

Unfortunately on the BMW 1150 a GS-911 just doesn't tell you much as it's usage & available information is pretty limited on the 1150 Ma 2.4. 

 

What is you warm engine idle RPM???? If under 1050 raise it a little. 

 

You might try riding with the o2 sensor disconnected as a test (see if your warm engine idle miss issue goes away).

 

Replace lower spark plugs & make darn sure the lower spark wires are FULLY seated in the coil.

 

Did you get the o2 sensor wire pig tail fully rerouted away from the  R/H lower spark plug wire (doesn't cross over it in close proximity or run along it in close proximity? 

 

 

[JamesW]

My money is on the good old BMW stick coils.  I think DR mentioned them in a previous post.  About the only way to find out is to install new ones.  Maybe buy just one coil to experiment with swapping out one at a time.  Don't waste your money buying a coil from good old BMW go to someone like Beemer Boneyard or www.euromotoelectrics.com.  These coils can be intermittent as I painfully learned about 13 years ago and 10K miles when my '04 R1150 was nearly new.  I wouldn't even be surprised if both your stick coils were acting up and your bike just runs only on the secondary plugs.  Both my stick coils finally failed completely in the middle of nowhere on the OR/NV boarder and I rode home about 200 miles on just the secondaries with the bike bucking and snorting with the occasional backfire.  Still irritates me when I think of it.  I mean stick coils are known to be pretty darn reliable but are a different story on early oilheads.  Glad my R1100RSL is pre-stck coil.  Grrrr.....