I think if you use a high quality Synthetic oil like Amsoil, Mobil 1, or some others that are SPECIFICALLY designed for the conditions our air cooled motors encounter, changing oil sooner than 5K is simply wasting the product, which is something none of us need to be doing. The exception to this rule are those who consistantly ride is extremely harsh conditions (heavy traffic, extreme dust, short rides where engine does not reach proper operating temps). Most of the people on this board RIDE their bikes from what I've read, and 5K between changes has been shown to be more than adequate. A K&N, Amsoil, or HD filter is fine for those change intervals, IMO. Prior to long term storage, a bike's fluids should always be changed, IMO.
BTW...I wouldn't run Syn3 in my lawnmower, and it's a HONDA.