In 'Tuning for Speed' Phil Vincent wrote "... the Speedway Vincent engine with standard 66 per cent factor caused severe vibration in a very light dirt-track frame until the factor was reduced to 61 percent, ..." I have two questions I hope someone can answer: 1) is the claimed dry weight of 390 lbs. I found on-line roughly correct for a pre-War Series A Comet, and 2) what was the weight of the Speedway Vincent?