Well, I couldn't leave well enough alone. Decided to put a Boyer on the 72 combat. Why? Dunno. I guess the bike was starting to run too well so I had to invent a problem. Anyhoo, I installed the system and now have absolulely no spark to the left cylinder. Rechecked all connections, then used the Old Britts troubleshooting guide. I ran a direct line from a fully charged battery to the black box white wire and touched the black/yellow and black/white black box lines together and separated them. Good spark on the right sparkplug, nothing on the left one. I then switched the coils with the same result so it seems the coils are fine. I'm guessing that the black box is kaput but I'd appreciate some feedback before I have to put out some more cash into another box. I enjoy a challenge as much as anyone else who finds therapy from working on Nortons. I could go back to the points but that's not the er, ah, point. Now it's the challenge! Debby, you can throw in an "I told you so!" cause I recall your good logic on keeping the poinst on another thread.