Wanted: A7 Star Twin long stroke engine

[pdg]

Hi,

I'm looking for a complete A7 Star Twin long stroke engine, preferably a 1949 if possible.

Many thanks, Peter.

[ChesterA7]

I've got a 48 engine if you're interested.

[pdg]

Before I get overly excited, does anyone know if there were any changes to the long stroked A7 engine between 1948 & 1949?

[trevinoz]

The Star Twin Has 2 carburetors, the standard A7 1.
That's the only differences that I am aware of.
Star Twin began in 1949.

[bikerjohndavies]

Hi Peter,
The Star Twin engine was introduced in 1949 with twin 275 carbs, larger valves, high compression and the engine number had a S added after the ZA7 so a standard engine was ZA7 nnnn whilst a Star Twin was ZA7S nnnn. The only difference between a 48 standard A7 engine and a 49 was the change of dynamo from the short E3H to the longer E3L that also meant a change to the front primary side engine plate. Star Twins were all plunger rear ends whilst an A7 could be rigid or plunger. The rigid frame number would start ZA7R and the plunger ZA7S. I believe that some rigid frames don't have R, just ZA7. There is no way of telling from the frame number if it started life as an standard A7 or a Star Twin. There were a number of changes between 48 and 49 in the frame and forks besides the introduction of the plunger rear end such as a 2 piece frame rather than a one piece, QD front and rear wheels and different forks. Hope that helps.
Is it really a Star Twin engine you want or just a 49 long stroke engine?
Cheers, John

[pdg]

Hi John,

Many thanks for your really useful message. I have a 1949 Star Twin at the moment. Ideally I'd like to try to find another Star Twin engine to work on, but if that fails I would settle for a "standard" long stroke engine.