Classic components – JAP part seven.
As the 1920s started, JAP faced stiffer opposition on the racing and record-breaking scene and were to encounter a similar situation in the supply of engines to their motorcycle factory customers.
Realising a changing market, JAP altered its advertising. Rather than rely on heavily promoting competition successes – as in the past and of which there was still many – the firm changed the slant of adverts week onweek, alternating between reliability competition gold medal awards, racing and hill climb victories, record breaking and campaigns extolling the four virtues of JAP engines: “Economy, Efficiency, Reliability and Speed.”
Unfortunately a few promotions were, shall we say, ‘inventive’ including the “New Lightweight Engine” announced Christmas 1921. Rather than new, the 293cc engine was a redesign of the existing 293cc unit whichwas marketed first before the First World War.
During May 1922, the factory announced a new* dohc 344cc engine with detachable iron cylinder head and huge, 1¾in exhaust valve set to one side. Developed by Sid Moramunder the gaze of Val Page and Bert Le Vack, the engine had potential but was virtually untested. Still, it was slotted into a New Imperial chassis for the IoM TT – risky! Ironically, the resulting public failure wasn’t down to the underdeveloped engine but a faulty gearbox.
Entered alongside sv and ohv JAPpoweredNew Imperials by the Birmingham factory, Le Vack’s ohc Junior machine powered down Bray Hill and set a new lap record fromastanding start of 56.46mph. After three laps, Bert led by over 1¾ minutes, with themotor humming – then the gearbox seized near Windy Corner.
The IoM and Le Vack were never good friends but there was some justice as he finished second in the 1923 Lightweight TT astride another New Imp, housing this time a 250cc ohc JAP (simply the 344cc unit with bore reduced to 62.5mm, which with 80mmstroke gave 245cc). The result was somewhat bittersweet for JAP, as the victorious NewGerrard (ridden by its maker Jock Porter) was powered by a 250cc ohv unit from up-and-coming rivals Blackburne.
Despite the success of ohv JAP engines and ohc development, an established side valve JAP design was the centre of another legend after the IoMTT races. On July 8, George Brough lined up his stripped SS80 Brough Superior at Brooklands for the three lap, over 560cc Solo Handicap Race with a 1m3sec advantage over scratchman Claude Temple (989cc eight-valve HarleyDavidson) to win at 82.08mph. This machine, later renamed ‘Old Bill,’ went onto to consecutively win 51 races and in the 52nd it crossed the line minus rider! It was the first side valve machine to lap
Brooklands at over 100mph.
JAP had little new to offer at the 1922 Olympia Showbut their year looked up as Bert Le Vack went on a series of marathon record-breaking sprees in November, using JAP power from 245 to 998cc.
In part to keep ahead of rivals, JAP began inviting pressmen to visit their factory to view their modern approach to engine building – what today we would call quality control and testing – with aHeenan and Froude Brake (Dynomometer).
And much publicity was afforded to an interview given by Bert Le Vack, then still in the employ of the Northumberland Park, Tottenham factory. Keeping the ball rolling, JAP then announced their first new engine of the year, the 346cc (74 x 80mm– so called short-stroke) sports engine with hemispherical detachable cylinder head fittedwith semi-tulip valves.