That is just one of many styling ques taken from the old bikes of the 60s. The primary cover , timing cover, and throttle bodies all harken back to the older bikes. Looks like even the configuration of the fins on the head does too, probably trying to take away from that ugly radiator that will be on there to get the people who like the nostalgia of yeasteryear.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!