Oh and one more thing: one of the reasons I purchased the DD16rr is exactly the different handling of the "double twin"...though it is a much more powerful bike (approx 20HP more than the F4) it's apparently much easier to handle and much more controllable with the trottle. But don't take me wrong now: they are both literally two "BEASTS" that deserve respect and all the attention you have in you in riding any of these two bikes totally out of the ordinary.