have you notice...
 

that right after he knocks ben out they said he left and you hear his bike driving off. when you get him out of the dumpster, his bike is there. I know this is probably on purpose...but still.

Bolus put on the jacket to imitate Ben and drove off to make the Polecats think Ben had driven off. When they hopped on their bikes and gave chase, Bolus hid alongside the road, doubled back, and dumped the bike and jacket, knowing that they were going to frame Ben and the Polecats for Corleys murder.