Yeah that's probably true as you've got cylinders opposed to each other like a multiplied extension of a perfect 90 degree v-twin depending on how it's arranged, but how big is that motor? Seven cylinders, I don't suppose it's much less than at least five litres maybe? In a lightweight hardtailed bike chassis I guess it must have at least some effect on what little mass it has around it, must take some nerve to ride it! I bet it sounds impressive enough though, silencing not so big a problem with an aeroplane.
QUOTE(Finn @ Apr 18 2007, 08:17 PM)

Not sure on this, but I though that the radial engines were vibration free which was one of the reasons they settled on that style ? Something to do with the cylinder firing order so that they cancel each other out.