after reading thru a lot of the old posts and stuff, it looks to me like on a bike, a lot of you guys are shifting gears at higher RPMs than i do. i have a 00 zx6r, which redlines at 14.5, and i usually shift at about 8K. will this bog my engine; is mileage better if you shift higher (that sounds counterintuitive, but i don't know much about bikes yet), or what?