AJS & Matchless Owners Club

Does anyone know where to obtain a timing gear cover gasket for a 1958 AJS 600 Twin? Found the original gasket split, when checking the timing.
Also to dynamically check the ignition timing, can you run the engine with the gear cover missing without spraying oil everywhere?

There never was a gasket fitted. Someone has made one. The factory recommended and used Wellseal. I use clear silicone but so Light that it won't blob and splill into the cases. Others use Hylomar Blue.

Thanks for advice , and explains why there isn't one listed on the AMOC club parts service.