Comments by "crazypj" (@1crazypj) on "PARALLEL TWIN: 360° vs 180° vs 270° - Ultra in-depth but EASY TO UNDERSTAND - ENGINE BALANCE" video.

  1. Have you looked at the Phil Irvin 76 degree Triumph twin from 1960's? There seems to be a LOT of confusion why it was done with the majority opinion that it was to reduce vibration. The way I read it though, it was to have one piston accelerate the flywheel to lower frictional losses, the lower vibration being a secondary plus point. Yamaha experimented 270 motors for the flat track XS650's in the 1970's but cranks always came apart when revved over 10,000rpm. (pressed up roller bearing crankshaft) They did get it right in the late 1980's though with the XT750 twin (and later TDM750/850)
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