He describes the 'big-bang' effect in terms of a communication process between the rider and rear tyre, made via the engine. A communication process which, in the case of a screamer design, becomes increasingly distorted at high rev/min. 'Big-bang' engines keep this distortion to a minimum.
"Internally the 'big-bang' engine is very smooth during its rotations. It sounds like it is fluctuating a lot, because of the uneven combustion timing, but the reality is that it is very smooth at high rpm," he began.
"The screamer engine
sounds very smooth, but over 12,000 rpm the motion of the moving parts inside the engine becomes a big problem. You can think of it as creating a big 'noise' that stops the rider from hearing what the tyre is 'saying' to him.
"The rider needs to listen carefully to the tyre and talk to it directly with the throttle, but the screamer engine makes it really hard to 'hear'. So the connection between throttle and tyre is not good with the screamer - don't explain this to the Kawasaki people!" he quipped. "I'm only joking!
"So the screamer engine sounds nice, but if the engine goes over 12,000 rpm then there are problems and in
MotoGP the useable rpm is 14,000 to 17,000 - sometimes up to 19,000 - so a
big 'noise' is happening at high rpm with a screamer and the rider cannot 'talk' to the tyre," he concluded.
Yamaha and Kawasaki both use an inline four-cylinder layout for their MotoGP engines, while Ducati, Honda and Suzuki use a V4 configuration.
