Misc: Ignition Are BTH ignitions wasted spark, firing every revolution?

[craig]

Are BTH ignitions wasted spark, firing every revolution?
They can be timed to either BTDC stroke?

 

[greg brillus]

Hi there Craig, No they are not.........only fire each plug on the compression stroke as per a standard magneto........most all of the newer electronic coil ignitions are wasted spark.......this works fine on most but not all twin engines.

 

[erik]

Wasted spark is with two ignitions every 180 Degrees which will work on a parallel Twin but not on a v Twin.For example the Boyer Bransden Ignition . Erik

 

[Bill Thomas]

It works on my Special, Vincent Twin, Eric, "D" Distributor and twin ended Coil.
Don't have to worry the leads are on wrong, Either will do.

Len Matthews told me how to do it, Essex.
Cheers Bill.

 

[Normski]

Works for Vincent and Guzzi V twins - it’s commonly done with Lucas Rita - the dwell angle must be quite different between cylinders though
.

 

[bmetcalf]

Ditto Airhead BMWs.

 

[Robert Watson]

I run a "fire them both" wasted spark ignition. It works just fine on the 50 degree Vincent and I was sure it would It is factory parts from a 45 degree Hardly Able son!

Also the Boyer on my BSA Rocket 3 fires them all together at 120 degrees.