The successful teams, and riders, in MotoGP seem to have something in common. They test thoroughly before the start of the season, find a good base setting for their bikes, and then simply fine tune from circuit to circuit. They do not make drastic changes from circuit to circuit during the year.
The same was true of many successful motocross riders I recall. Find a good base set-up for your bike, start there at every track, and fine tune based on individual track characteristics (but do not stray too far from your base settings). If you think about it, this allows the rider to become familiar with the bike’s characteristics throughout the season, rather than trying to learn a “new bike” every weekend. If you know your bike’s flaws, at least experience will teach you to ride around those flaws, to some degree. If your bike has drastically different settings, and a drastically difference balance, virtually every week, you are probably going backwards, rather than forwards. This seemed to be Yamaha’s problem last year, but Valentino Rossi seems to be taking the better approach at Yamaha — working quickly during the off season to find a reasonably good base setting, both for the engine and the chassis, and then simply fine tuning the bike from there. The more I think about it, Rossi will make many significant changes at Yamaha — virtually all of them for Yamaha’s betterment.