Every year we travel to the Netley Marsh Eurojumble to hunt for spares, in 2015 this bike was for sale at a French stall. It looked like an interesting BSA M23 Empire star project with a nice JM23 engine but sadly had a later WDM20 frame fitted which it made looks like a collection of parts. But at closer look it was clear that beside the frame all other parts were genuine Empire Star so it still had potential but we more or less forget about it. On the Sunday after Netley we were at the Beaulieu jumble and ran into the very nice French seller and he told us the bike was not sold on the jumble. After some negotiation we agreed that we would buy the bike if the crankcase was matching and had no damage. Later that day we inspected the engine, it looked fine and the deal was done.
The M23 Empire Star model was called: “the masterpiece of the industry” and came in 1937 and was the top of range M-model. In fact it was a specially tuned M22 with a high compression piston, higher inlet cam and bigger carburettor. It came with a 20 inch frontwheel and with a fresh looking ”Empire Star Green’ colour and a golden star on the tankpanels.
Above a drawing of the M23, this one has a single port head with but the two-port head with upswept pipes on both sides of the bike was a popular option.
Here some more pictures of the bike how we found it: note the panel in the tank, the nice aluminium rockerbox and big 289 carburettor, must be one of the prettiest engines ever made!!
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The prefix J on the enginenumber indicates 1938,
We removed most of the rust and dissolved varies layer of paint from the petroltank with the help of paintstripper. To our surprise all the layers of paint quickly dissolved expect the last layer of paint which turned out to be a very thin but though layer of the original ”Empire Star Green”. So the tank is back in original colour again! BSA surely knew their paint in those days!
Also the oiltank was attacked with paintstripper and great chrome appeared again!
It still had the later War Department M20 frame fitted, which is dimensionally the same as the 1938 M23 frame but has quite some differences in detail. The most important is the way the oil-tank is fitted. The 1937-38 models had a plain rectangular shaped oiltank which was fitted onto protruding 2 strips on the frontframe, whether the later models had a larger capacity oiltank more wrapped around the rear mudguard and fitted on a square plate behind the frontframe. This WD frame was quickly sold and with the help of some contacts we managed to buy a HM20 frame, this is a 1937 frame but beside the number exactly the same as the 1938 one
All cycle part were fitted on this frame and engine has been rebuild, sadly no pictures were taken during engine rebuilt…..
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This below is the present state, isn’t it a great looking bike ??
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Although it looks quite complete now it is still needs a lot of work but we decided to put it together and leave it for the future to focus on other projects first, will be continued for sure!