I am not a mechanic or an engineer. However I have done more engineering than most of the engineers with whom I have ever worked. My last job was 'on contract' project managing the development of an engineered product. My boss was an engineer. When I showed him my Seeley 850, he said ' I am impressed'. I have been fitting different motors into different frames for more than 60 years. When I build a bike, I build it in my head from experience before I buy any parts. When I bought the Seeley rolling chassis, I had raced against it when it was a Seeley Laverda 750. An idiot pulled it apart to make it go faster when anyone who looked at the exhaust system should have known why it was slow. By the time I got the frame, the fuel tank was badly corroded. I also wanted the Laverda 750 motor, but the guy who had it wanted too much money. Theoretically I owned that motor. I think the Commando 850 motor turned out to be better anyway - it is a lot lighter, and just as quick as the Laverda 750 would have become..