No spark at rear cylinder. Front fires fine. New plugs wires and coil- same symptoms. What should I look for next? Thanks

 

Single fire or duel? 9 outta 10 times it's the coil.

 

Not sure of single or dual. It is a buddys bike 20 miles away. 91 heritage. He said he changed coil. He thinks it is stock. What is the 1 out of ten? I have an 82 FXWG with points in it now.