secondary spark plug

[coolrider]

Perhaps somebody can explain what is the purpose of secondary spark plug on a GS engine. Is it for power efficiency or just better emission?
Is it inside or outside the combustion chamber?
Thanks.

[mikec]

In the previous BMW motorcycle two-spark engines, the plugs fired together to for a better fuel burn. The setup on the R1200GS can is different as ECU interprets throttle, lambda & anti-knock sensors and can stagger the ignition timing of the two sets of plugs so the engine runs smoother. This set up is supposed to make the engine run smoother.

By the way, I asked a tech at the shop about this. Heck, I didn't know either.

Mike

[coolrider]

Mike, thanks for sharing.
I was asking this because I'm about to temporarily install wide band commander to see what AFR this bike is running on.
To have a good AFR reading, there shouldn't be any active emission reducer such as PAIR Valve.
At first, I thought secondary plug is a kind of emission reducer, but from the explanation, my understanding is that they are both active inside combustion chamber.

[mikec]

Originally Posted by coolrider

Mike, thanks for sharing.

At first, I thought secondary plug is a kind of emission reducer, but from the explanation, my understanding is that they are both active inside combustion chamber.

Coolrider, the tech said they are, indeed, both active.

Mike

[roamingbeemer]

I am curious if the new 2010 dohc 1200 gs has a secondary plug. I only have the Hayes manual for the 09. I read the dohc model is single ignition but since my 2011 is new I have not had a need to really investigate.