spark or no

Hey all, thanks for the add to the group. I have an odd issue with my rear coils. Its an 85 VMX 1200 which I've owned since 1992. They have spark at cranking, but not at idle. If i rev the bike past 2k rpm, they fire but not perfect. Coils test= 3 ohm primary, 16.3 secondary. P/U test=...