Its 420cc engine developed from that of the humble C15 250 roadster, Jeff Smith's works BSA moto-crosser produced more power than it could reliably handle, resulting in a comprehensive engine redesign for 1964. For the new season the works '420' had a much stronger crankcase with revised main bearings; the C15's drive-side ball race and timing-side plain bush being superseded by a roller bearing and ball race respectively. Also new was a light-alloy cylinder with chromium-plated bore, which allowed a useful increase in compression ratio thanks to its superior heat dissipation. Installed in the Brian Martin-designed all-welded frame, developed on the works 250s, this heavily revised engine made the new Victor Grand Prix a world-beater - Smith taking the 1964 Moto-Cross World Championship with seven wins in the 14-race series. The new crankcase permitted a further lengthening of the stroke to 90mm for a capacity of 441cc, and in this form the Victor GP moto-crosser went into production in 1965. Smith took the world title again that year on the works B44GP.
One of approximately 468 built, this original and un-restored Victor GP has been in the present ownership for circa 30 years. We are advised that the (original) engine has just been rebuilt by RTS, leaving the fortunate new owner of this ultra-rare machine to complete its sympathetic re-commissioning.