"The older I get, the faster I was"?
"Dress for the slide, not the ride"
"Slow in, fast out" (Bends / Curves you dirty minds!) or, "Keep it between the hedgerows"
"See God, then back off" Kevin Schwantz #34 I believe.
Conversley,
"The throttle goes both ways"
and finally, my favourite T shirt:
"Young riders pick a destination and ride. Old riders pick a direction and ride!"