Plummer’s nightmare
More from Tim Gibbes in NZ: “A while ago we were talking about Vic Plummer’s V4 Triumph referencing OBA #41 Classic Cob. Arthur Harris has just sent me the photos he had which are dated Feb 1965 which I think must be when the motor was fitted to a Manx frame in UK. Arthur was in NZ for the 1963/4 International MX Series and bought the V4 motor as an investment, took it back to UK and sold it, so I assume the guy who’s standing by the V4 Triton in the attached picture is the UK owner. Looking at the detail, he’s certainly done a great job of siamising the two units with the technology available in those days. Looks to me like an early Burman gearbox, the one with the die cast positive stop mechanism that broke a lot and I see the clutch springs are screwed up tight indicating possible clutch slip. How the carburation would have worked is a puzzle with the 2 bellmouths facing each other. Notice he’s chopped off the rear timing cover as he didn’t need it with the 4 cylinder distributor. I wonder how it went in practice? Arthur Harris was quite a good engineer himself and made his MX bikes, plus had an engineering business in UK, but now lives in France. In a letter to me this year Arthur says, ‘A lot of thought went into creating the engine – he didn’t design it on the end of a fag packet! It’s all very well cutting off two parts of a pair of crankcases and welding them together, but keeping them square and reducing distortion to a minimum must have been a task on its own. Also the welding techniques then and today are vastly different. I imagine coupling the two engines together was via a short gear train as a chain would not give a positive balance between the two crankshafts to give a balanced exhaust beat’.”