my trouble keeps returning. my 1984 virago 1000 back plug stops firing, I am new to club and welcome any insight to make this go away. tks

Firstly it check the HT lead is fitted snuggly, then change the plugs.

If this still plays up then id say its a potential coil failure, replace both front and rear coils and go from there.

 

Can you swap the coils and leads front to back.

See if the proplem moves too.