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Historic Motor Cycle Racing Register of South Australia

Len Bowes ?

JAP V twin with heads that have their inlet ports in the "V" connected to a single carburetor by the looks of it. 😉 "8/75" was the model designation of a 1000cc V twin engine that saw very limited production in 1934-5. It was used in I think about 8 production Brough Superiors and a similar number of built-to-order Morgan 3 wheeler cars. I think one engine may have made it's way into a Zenith motorcycle as well. By the mid-30s JAP had been a bit too late sticking with their old and outdated V twins whose designs dated from the earl-mid '20s and needed updating if they were to remain competitive in the market. But the depression had caused JAP to shift their efforts and manufacturing towards industrial motors, because the market for motorcycles had dried up. They did, belatedly, in about '34 design the 8/75 engine that was what the market wanted, something more oil tight, with a recirculating oil system and with increased reliability. But competitors had moved to fill the hole in the market that JAP had created, Matchless designed and built a new V twin engine for the upper end of the market that was oil tight and reliable. Morgans had already changed over from JAP to Matchless in '34 and Brough Superior was in the process of changing over as well. The Matchless engine was simply cheaper and proven by the time JAP had tried to launch their improved design. JAP had lost the bigger bike prestige market. However, they did make an attempt to gain publicity by dragging out one of their old designs in about '36 and using a few parts from them, cobbled together the legendary 8/80 racing-only engine, the forerunner of which was in fact used in Eric Fernhough's world land speed record breaking mototcycle that went on to become the engine to beat in speedway sidecars, sprint racing and hillclimb cars right into the immediate post war years. There's a lot more to the story, but that's about it in a nutshell, as far as I am aware.

Evette Franklin ask Phil