Secondary Spark Plugs

[Dave_zoom_zoom]

I have a 2006 R1200RT. If this topic has been discussed, please forgive me.

 

What is it that tells the secondary plugs when to fire? When to stop?

 

If it is at a given RPM's, what are they?

 

Thanks

Dave

[dirtrider]

I have a 2006 R1200RT. If this topic has been discussed, please forgive me.

 

What is it that tells the secondary plugs when to fire? When to stop?

 

If it is at a given RPM's, what are they?

 

 

Afternoon Dave

 

The secondary (lower) spark plugs are controlled by the same main fueling computer (just different output drivers). The (base) spark timing is triggered by the very same crankshaft sensor as the primaries are but the fueling computer (BMS-K) modifies the actual spark timing based on RPM, throttle position, engine temperature, engine load, knock sensor input, etc)

 

At lower RPM's both the upper (primary) & lower (secondary) plugs spark at the same time & same timing.

 

At higher RPM's the lower spark plugs are phase shifted by the fueling computer to basically be phase shifted out of operation. They still spark but are so far out of time that they do nothing as far a cylinder ignition goes.

[Dave_zoom_zoom]

I have a 2006 R1200RT. If this topic has been discussed, please forgive me.

 

What is it that tells the secondary plugs when to fire? When to stop?

 

If it is at a given RPM's, what are they?

 

 

Afternoon Dave

 

The secondary (lower) spark plugs are controlled by the same main fueling computer (just different output drivers). The (base) spark timing is triggered by the very same crankshaft sensor as the primaries are but the fueling computer (BMS-K) modifies the actual spark timing based on RPM, throttle position, engine temperature, engine load, knock sensor input, etc)

 

At lower RPM's both the upper (primary) & lower (secondary) plugs spark at the same time & same timing.

 

At higher RPM's the lower spark plugs are phase shifted by the fueling computer to basically be phase shifted out of operation. They still spark but are so far out of time that they do nothing as far a cylinder ignition goes.

 

 

 

Thanks DR!

 

Wow! That's a lot of inputs that are controlling the secondary plugs. I thought it may be something simple like the RPM's only. Well, that (BMS-K) seems to know what it's doing. I'm happy with the results. I have no problems.

 

I'm most almost always running at higher RPM's (4,000 or more) and find my primary plugs and muffler exhaust are always very clean. However, the secondary plugs become a bit smoky. Would it be recommended to change or clean the secondary more often then the primary plugs? Or am I just nit picking?

 

Thank You

Dave

[Gene#3]

You can always "rotate them" every thousand miles if you're REALLY looking for something to do... ;-)

[BriSco]

For what it's worth, I rotate mine each valve adjustment. I don't know if it helps anything but it makes me feel better.