Running rough

[Spotlight Kid]

My 07 1200GS is running strangely. Starts first touch and accelerates all the way to 100+ but holding the revs around 3000rpm in a low gear and it feels as though its missing. Lumpy and uncomfortable. Local guy checked the vacuum on both inlets and they are fine. Checked compression Great and changed spark plugs. No different so ran the BMW diagnostic check thingy on laptop connected to multipin under seat. No problems reported. Ive put a couple of tankfulls through with Redex injector cleaner and thats not done anything. Could it be electrical? Coils?

Thanks John

 

[Steptoe]

Does your local guy know about BMW's ? or is it the usual motorcycle shop who's an expert on every motorcycle........... the type of shop that calls me two or three times a day with bmw problems they can't sort out.

Has he checked the coil sticks ? They don't show up on any diagnostics.

No special equipment needed. Just common sense. Run the engine with only one connected on each side, then swop to the secondary and run it on those only. . The side that doesn't run gives you a clue where the problem is

 

[Spotlight Kid]

Common Sense. Whats that?

Ah Common Sense! There in lies the problem. Do you mean disconnect the secondary plugs underneath and run it and then reconnect connect those and disconnect the two main plugs running through the valve covers?

thanks John

 

[Steptoe]

Ah Common Sense! There in lies the problem. Do you mean disconnect the secondary plugs underneath and run it and then reconnect connect those and disconnect the two main plugs running through the valve covers?

thanks John

You've got it

 

[Bendy toy]

The old coils are lucky to last 5 years or 50K miles. DO the primary sticks smell burnt?

 

[Spotlight Kid]

You've got it

Great Ill give it a go tomorrow and let you know

thanks John

 

[Rusty Bolts]

Sorry to bump in on this but I am experiencing the same problem on my 07 GS.
If I have interpreted it correctly, you disconnect the lowers and go for a ride. Then reconnect the lowers and disconnect the uppers and go for a ride whilst noting any differences
I did that and on the ride the rough running became slightly worse when running on just the uppers. I rode it on just the lower and it would tick over fine but when you pull off from anything but a gentle acceleration it would cut out. If you were to release the throttle it would pick back up and hold the speed (not big numbers i.e. 30 MPH). So does this indicate that my lowers are on their way out or does mean that it is normal for the lowers to not work under hard acceleration?
Or
Have I got it all wrong and the whole disconnect thing is done whilst on the centre stand and not going any where?

 

[B4ndit]

First of all whip them all out. A malfunctioning coil is usually obvious once you look at it. Shorting burns, bad condition, rust etc. Next follow Steptoes instructions and because you are running only one coil at a time on each cylinder it becomes obvious which one isnt working. No need to ride the bike.

Personally I haven't needed to do this on a GS but have had the problem a couple of times on cars. Both times it has been coils shorting to the cylinder head and you get grey shorting marks on the failed coils. On a car you swap out the whole pack. On a GS you have the luxury of just doing one coil. Cost isn't comparable though.

 

[Spotlight Kid]

Thanks Guys but I followed instructions and disconnected the secondary plugs first and started the bike just on the primary plugs. No difference still hunting. Re connected and removed primary leads and started on bottom secondary plugs. Just the same. Maybe trip to the dreaded BMW main dealership. Ill just have to sell a kidney but its Ok though as I have heard you dont need them both. Straws and clutching. Fuel filter/air filter?? Valve clearances??

Thanks will let you know

 

[Beemerman59]

Thanks Guys but I followed instructions and disconnected the secondary plugs first and started the bike just on the primary plugs. No difference still hunting. Re connected and removed primary leads and started on bottom secondary plugs. Just the same. Maybe trip to the dreaded BMW main dealership. Ill just have to sell a kidney but its Ok though as I have heard you dont need them both. Straws and clutching. Fuel filter/air filter?? Valve clearances??

Thanks will let you know

I would still do the coil disconnect routine but take the bike out and put it under some load.

 

[Bendy toy]

Do the primary coils smell of hot electrical varnish?


Sent from a widget that can't spell.

 

[alex_rsa]

Do one coil at a time. Disconnect 3 of them and start the bike. If it starts, coil is ok.

Do not let it run as you are dumping unburnt fuel into the exhaust. I found (and I have had 2 coils go) this process reliable.

You can then swap the coil over to the other side to verify it is not the wiring or spark plug causing the issue.



Alex

 

[Spotlight Kid]

I have ridden over to Rotherham this morning to Rainbow BMW. Not used them before but they promised to have a quick look. They took the bike out for a ride and then checked all the coils and ran a diagnostic. No major faults but they spent 30 minutes on the bike and charged me zip. I needed reassuring that it was sound as I'm off to Spain in 3 weeks so I can live with it till I come back. Im booking it in for an early 36000 mile service and they have mentioned a software update that might help. Top guys. Great service. Thats the way to do it

john

 

[Rusty Bolts]

I have found one upper coil that has a weak spark but passed muster in the spark plug check thingy. I removed 1 stick coil and put an old spark plug in it The bike won't run if you take a plug out
Fired up the engine whilst holding the plug against a suitable bolt for an earth (Valve cover bolt). It had a nice blue spark. However, if I moved it away from the earth the spark would stop arcing after about 6mm. The other coils would be sparking away at up to 25mm away from the earth point. I have changed it for another coil I had lying around that gave a big fat spark.
Unfortunately, the lumpiness is still there. I have changed the TPS (and done the rest procedure), the FPC, checked each of the 4 coils is jumping a gap of at least 19mm, put new plugs in, stripped down and checked the kill switch and starter button (and put contact treatment in it), checked the ignition barrel connectors, given the side stand switch a good waggle, soaked the gear position sensor in WD40, checked all the electrical connectors for corrosion, checked for trapped fuel lines and breathers, checked the throttle body balance. Each change, check was followed by a ride out to check if it had improved. Not sure there is much left to check.
This all seems to have come to notice since the bike was Serviced and had a new fuel pump fitted under the recall. I think it is coincidental though. The only thing that I can think of is the alternator needs changing as the bearings are tight. This is due to be done next week so I can only wait and see.

 

[Pukmeister]

Checked your air filter and inlet snorkel are clear? No air leaks on throttle body inlet rubbers and rubber bungs over the synch test points?

Got access to a GS911 to check real-time sensor values and fault codes eg air inlet temp, oil temp, cylinder temps, lambda traces?

 

[Rusty Bolts]

Good points. I don't have a GS911 so can't check those, although I could whip the lambdas out to see if they are sooty. They have been out before and reassembled with cooper grease so should not be a problem.
But have checked the air filter and snorkel and the Sync blanks are in place and not split. I fear it will be the main Dealers.

 

[Pukmeister]

Thanks Guys but I followed instructions .........No difference still hunting.

If it's hunting at idle, it could be an air leak between a throttle body and cylinder or possibly the idle speed stepper motors need re calibrating, assuming throttle cables have enough slack, valve clearances are correct and throttle bodies are synchronised.

 

[Damaxta]

Buy a new primary coil. You'll need it someday. Then change one after the other, to identify if it solves the problem.

I think the secondary plugs are more important at idle, effectively an emission control thing. Problem is the secondaries are more expensive and specific to left and right. The primaries aren't. The bike should run fine on just primaries, so my guess would be one of the primary coils.

If you open the power quickly to full from 3k, does the bike miss ? If so... Coil.


For those who believe, no explanation is necessary.

For those who do not, none will suffice

 

[Bendy toy]

Secondaries could be ordinary three wire stick coils from a car parts supplier. Put them under petrol tank and connect with HT leads.


Sent from a widget that can't spell.

 

[Rusty Bolts]

Well a front to back split of the casing and a displaced magnet in the alternator would do it. All sorted thanks to the great chaps at CWs in Dorchester.