The idea is that by moving your weight out (and thus moving the center of gravity out) you don't need to lean the bike as far for a given speed. In that way you stay on a fatter part of the tire or don't scrape parts of the bike on the floor. Or to put it another way you can go faster for a given amount of lean. The G.P. boys etc. sometimes use the knee on the floor to recover from a front end break-away. I wouldn't fancy your chances of that with a Fazer though!
Personally I'm the old school type of guy and keep everything tucked in.
Personally I'm the old school type of guy and keep everything tucked in.