virago only fires on one cylinder

I have a 1982 yamaha virago xv750j   It doesn't fire on the front cylinder.  I have tested the stator, pick-up coils, ignition coils and lead wires,  I checked and cleaned all my connections and put in new plugs.  The dealer will not test the CDI box,  and I don't know if the CDI would do that.  Any help would be greatly appreciated.  Oh I did find a nick in one of the wires going to the front cylinders pick-up coil, right near the coil,  I don't see where it could have been hitting but I fixed that with electrical tape for now  but it tests good before and after the fix.  I would sure appreciate any help.  Thanks.