 The demise of the Lucas magneto was a prime reason that BSA and Triumph reconfigured their pre-unit-construction parallel twins into engines with integral gearboxes, simultaneously converting the ignition system from magneto to battery & coil.The Gold Star was not considered for progression to unit-construction, and instead the 250 cc BSA C15 was developed (via the B40) into the 500 cc B50.Although the B50 never attained the kudos of the DBD34, a B50 fielded by Mead & Tomkinson once held the class lap record in the Production TT, as well as gaining results at the 24-hour endurance races the Le Mans Bol d'Or and at the Montjuïc circuit in Barcelona.