Hi Bill,
To be honest I don't know for sure what the 'S' stands for, but these cams were used in the Bullet's last couple of years' production, as far as I am aware. There was also an'R' profile set of cams made by the Redditch factory, my Father's late fifties 350 has a set of these and with various other mods can see 90 mph flat out and is a quick bike. The 'S' cams for the Electra X came about by pure chance, while I was working on the Hitchcocks testbed machine for their tuning kit for these machines - I had tried all sorts of cams, various timings, double valve springs, you name it in an attempt to get past 5,800 rpm. Some cams increased the power up to this engine speed, but we were stuck with a top speed in the high 80's, due to inlet valve bounce restricting the revs. I had a couple of sets of old 'S' cams lying around and, just so I had left no stone unturned, I fitted a set [they don't look very exciting]. I realised I was onto something when I hit 95 mph in 4th gear and in top, flat on the tank, I got 103 mph, this with a very loud exhaust and 36mm Amal MK II. It also ripped twelve teeth in a row off the [detatchable] rear sprocket, as witnessed by some surging from the rear end which made me throttle off rather quickly !
My 'S' cams are copied from a set of Redditch 'S' cams which were used as masters for the first batch, the cam makers have this profile 'on file' now and can make them to demand, although sometimes they take a while to deliver !
Regards,
Paul.