Sparks per revolution

[bazbo]

Hi all

I have a suzuki smx50 supermotard, which has the same 2 stroke engine as the rmx50 and the old rg50.

Here is an oddity I have found with this bike.
I have just fitted an electronic tacho, and found that it need to be set to receive 2 sparks per revolution, otherwise it would read double the rpm.
Checked this with a little digital tachometer and confirmed that if the tachos are set to single cylinder 2 stroke settings (1 spark per revolution) then they read double.
So this indicates the the ignition is sparking twice per revolution, which is kinda odd. I have heard about 4 stroke wasted spark ignitions, but not 2 stroke.
Any ideas anyone? It's not an issue for me as my tacho can be set to 4stroke/4cylinder / 2 stroke 2 cylinder and then it reads correctly. I'd just like to know why!!!
B

[F5 Dave]

Lots of bikes have wasted spark usually not a problem except on methanol which can ignite at BDC apparently. However many singles have a pulsar coil and one pickup. I handled an RG stator and flywheel the day before yesterday when I picked it up looking for something else, but I can't recall the setup, some coils were missing though.

[Muciek]

It does have propably magnet type CDI that uses cdi charging coil as pick up coil, there are 4 magnets in so it fires 2 times per revolution.It's common on twins like snowmobiles