2&3 ignition not working

[Gorgonzola]

I've got a '72 750 that I'm having ignition issues with and I'm stumped at this point. It's not firing on cylinders 2&3. When I put the timing light on the cables I get nothing. The PO had a dyna electric ignition installed so there's no points. I've tried the following this far in incremental steps.

Checking plug gaps
Switching plugs
Switching plug wires
Switching coils
Switching the pickups on the dyna ignition

No matter what I do there's nothing going to cylinders 2&3.

Any advice on what to try next?

 

[dirtdigger]

check make sure you have 12 volts to both coils

 

[Gorgonzola]

check make sure you have 12 volts to both coils

They've both got 12v to them

 

[Gorgonzola]

It ended up being the main fuse. It wasn't totally blown, because everything else on the bike worked, but it was apparently not working 100%. I changed it and started firing on all cylinders.