Dismount your bike at any time:
While racing, bring your bike to a complete stop. Hold L1+ R1+ up, and your 
biker will get off his bike and start running.

Realistic Counter-Steering:
When your speed reaches approximately 100+, you'll see the rider tuck into 
a racing crouch. You can now counter-steer. When you turn right with the 
direction arrows, press L1. And naturally, press R1 while turn left with the 
direction arrows. Ride the center line for best results, it's quicker to avoid traffic 
going in both directions. If anyone knows how to get a better bike for free, 
let me know.