This is probably obvious to 'hardened' Norton owners, but I thought I would share my recent experience in the hope it might help someone just starting out.
I bought a 650SS in July '16. It appeared to be in good, standard condtion, but proved to be very much otherwise!
To cut a (very) long story short, after a major overhaul of the engine, I thought it was running OK but it developed a problem on a 40 mile ride: as I was nearly home, it started to 'miss'. This got worse and worse until it finally cut out altogether. I pulled over and kicked it and it started immediately. When I pushed it off the stand, it cut out. It started again, no problem, but when I tried to pull away, it cut out. At the third attempt, I was able to pull away and struggle the last 2 miles home.
My thoughts were carburetion. I checked the fuel filler cap and cleaned it out. Then I checked and adjusted the levels in the float chambers. The bike started and idled perfectly, so I went to take it for a test run. As I tried to pull away, it cut out. Keeping the revs up, I pulled out of our estate, but it cut out again so I returned home.
The next test was to spray WD40 around the manifolds to check for leaks, but it checked out OK. I then re-adjusted the float levels back to where they were (low, according to Amal wisdom) and ran the engine again. It started on 'half' a kick and idled well. When I tried to get it off the centre stand it cut out! Started the engine again, no problem and this time I tried wiggling the handlebars. Sure enough, it cut out! Electrical problem! I checked the connections to the ignition switch and felt the spade connectors weren't as tight as they could be. I squeezed the connectors together and went for a test run. Everything was fine - the bike ran well and picked up immediaterly from 3000 rpm. I have yet to test it on a longer run, but I have hopes!
What I have learned from this is that the problem isn't necessarily what you first thought it was!
I sympathize, it seldom is!
I had this happen on my 1966 N15CS, and the motor cut out on the Purley Way at night. Luckly it was mostly down hill, so I pushed it home. I lived off of the Purley Way back then. When I got home I found out is was the cut our button that cased the motor to cut out.
I too have had an ignition failure on my 650SS, the cause of which was the cut-out button, a typical aftermarket job. A new one sorted the problem, but I don't trust them now! If I have a starting issue, one of the first things I do is to disconnect the cut-out wire at the mag end, as a process of elimination.
Thank for the comments - it's nice to know you aren't alone!