Alloy head for ES2 pre-1950

Werner,

Roy Bacon's Norton Singles book lists ES2 alloy heads as from 1953 on.

iain.

The 500T had an ally head and was produced from 1949, so you would be ok to use it

Nice looking bike. John

As far as I know, the first 500Ts had iron barrels and heads. So, it may have been 1950 before the aluminium heads were available. I am not an authority on these bikes, this is just information I have picked up because I ride a 500T. It is probably worth contacting the club's technical officer, for pushrod singles, for a definitive answer. I have also heard that he may know a bit about tuning them!

Rod

Hi Werner,

The production 500T was first shown in public at the 1948 Earls Court Motorcycle show. This allowed me to use one of these engines in UK vintage racing in the pre 1949 class. The original alloy heads were sand-cast with a spectacle shaped iron insert which provided the valve seats and spark plug threaded area. This was used with the Alfin alloy barrel and these items used a 1/4 inch spigot when the cast iron ES2 engine used a 3/8th inch spigot. The casting process was changed in 1953 to the Welworthy Alfin die-cast type which had the full iron skull. This head was subsequently used on all pushrod single OHV engines for the 1955 season. I would think you could get away with using either of these as the later one cannot use as high a compression as the early type. You will need to get a post 1954 barrel to suit or modify your old barrel to fit and use a spacer underneath. Check the thread on ES2 pistons recently on this blog for more info. Regards, Richard.

There is a compleete 1948 500T engine for sale at eBaynr: 231796900655.

Regards from Svein.