Oil is actually pumped from the sump to the filter then back to the tank and then to the engine by an oil pump located on the right (as you sit on the bike) side of the engine just behind the cam cover. Doug
I've worked on were jappas, but I'm pretty certain the lubrication is pumped through the crank from an externally mounted tank, the pump is driven directly from the crankshaft and scavenged in a similar manner.
