I am not mechanically minded Long Eye.
I would say however, in defense of my argument, that the 2-Valve Engine is easier to maintain. The Riders in the old days were not having to pay very expensive Tuners as they are today - a lot of them maintained there own Engines. These days, by the time the Rider has bought his new Titanium Parts for his Engine and everything else that is required to make it (the Bike) go faster it Costs him a fortune, this is passed on to the Promoter by way of increased Wage demands which, in turn, is passed on to us Supporters at the Gate.
Now I have Supported Speedway for a very long time and the Racing today is, in my opinion, not as good as what we used to watch years ago. A lot of things contribute to this - but - to my mind Speedway is a diminishing spectacle to what it used to be.
You go to Speedway to watch RACING. The racing nowadays is certainly not that much better when you consider the COSTS of 4-Valve and Laydown Engines against that of the 2-Valve Engine years ago. Pounds definitely do NOT = Improvement.
Added to that - there were injuries back in the Seventies but certainly not as many as there are these days. To me - this alone would be reason enough to retun to 2-Valve Engines - I DON'T like seeing Riders hurt. That is happening far too often at the moment.