Press R + A and turn when in a burnout.
When delivering a bike and Cass and his gang appear, they will try to knock you off your bike by swerving in front of you. This causes you to wipe out, losing 200 style points and a large amount of your bike's health. To avoid losing style points, wiping out, and damaging your chopper, press R (the front brake). Cass or one of his friends will hit you, but they will fall off their bike and you will receive 150 style points.
When you are racing against Iron Horse, try to get close to as many cars as possible. This will earn 75 style points for each car you get close to without hitting. This will allow you to get more style points than Iron Horse. Remember you must stay ahead of him in speed.