What Is The Difference Between A Flat And A Crossplane Crankshaft?

If you have listened to Yamaha’s YZF-R1-based Superbikes at a racetrack, you may have noticed they have a sort of V-8 sound. Part of the reason for that is the crossplane crankshaft, which has 90-degree crankpins, not the 180-degree pins of a Honda CBR600RR or a Suzuki GSX-R750.