>You can do it. There is only 1 crank position sensor, so both coils have to fire for both cylinders.

If I follow this, & if I understand the 270 crank/cam timing, #2 is in the middle of an intake stroke when #1 is at TDC on compression.
Also, #1 is in the middle of a compression stroke when #2 is at TDC on exhaust (wasted spark time).
It seems unlikely that both coils fire in either of these situations;-)

>Firing both coils twice per revolution cuts down on the magnetic saturation time.

My belief is that the bottleneck here is at the pickup coil.

How can this be?
My guess is there's some magic in the CDI that sorts out The #1 & #2 triggers based on timing.

This belief system also helps explain a couple of other things:
1. No aftermarket CDI for 270.
2. Blown airbox on cranking (CDI initially confused @ cranking speed).

Said Molly to James, that's a fine motorbike. Richard Thompson