no spark on one cylinder

I have a 1984 Honda 750 Shadow.
Each cylinder has 2 spark plugs.
The front cylinder is working fine but the back has no spark.
I just got the bike so am not familiar with what the previous owner
has done.
I swapped electronic ignition and coils. But the same cylinder is not
firing.
I do know the wiring at the key switch is messed up.
Does the ignition switch send power to the two coils seperately?

wrote in
@n15g2000prd.googlegroups.com:

> I have a 1984 Honda 750 Shadow.
> Each cylinder has 2 spark plugs.
> The front cylinder is working fine but the back has no spark.
> I just got the bike so am not familiar with what the previous owner
> has done.
> I swapped electronic ignition and coils. But the same cylinder is not
> firing.
> I do know the wiring at the key switch is messed up.
> Does the ignition switch send power to the two coils seperately?
>
>

the 750 should be a 4cyl bike.. not two spark plugs per cyl.
have you pulled the plug and grounded it to watch to see if it sparks?
have you changed the plug?
checked power going to the coil?
checked the plug lead with a omm meter?
checked compression in the cyl?
thats the way i would start.

nut