I understand a little better with the "early 1969" date for your bike. I left for the US in June 1968 and we'd only found the problem a few weeks earlier. I got the impression, from talking to Peter Inchley when the M-X team were in Seattle in the fall of '69, that they had solved the problem prior to the Stormer entering the retail marketplace. It was still "in development" when I left.
Maybe if you got in touch with "Fluff" Brown's son, who I understand is still running the AJS business, he'd be able to advise if there was a fix. From what you've said about the ridges and damaged cooling fins, that bike was too early to have it. I'd suggested thicker and bigger fins in that area and a "bridge" in the fin configuration that would conduct more heat away from the center of the exhaust port. As I remember, there was no heat conducting material directly across the bridge in the liner, which was there to prevent the rings from snagging on such a wide port opening.
When you get to where it will be runnable, I'd strongly advise running with a Castrol "R" or equivalent oil in the gas unless you've heard from AJS what the fix was.
The Stormer is a fine machine to ride. I thoroughly enjoyed my daily commute on it, even though it was only about 10 miles each way. When I was commuting almost 50 miles each way, my ride was a rather tired old company 650SS. Despite it having 130,000 miles on it (according to the odometer) that was a good ride, almost all on country roads with very little traffic. When the 650 went back to London for a development program, it was a shock to get a 50cc Italian bike called a "MOTOM" for the trip. The Villiers "Fantabulous" scooter (a 200cc machine made in India) was an improvement over the Motom, but I was sure glad to get the 650 back again. Unfortunately, riding it back from my home town in Lancashire just before I left the company, the oil tank split open when I was cruising on the M6 at about 85 mph, and the engine seized. I don't think the old girl was ever repaired.
ex-Norton Villiers - Marston Road
Develpment & Competition Department