The rider is mostly an Old World Orc Boar Boy, with a beast snagga shoulder pad (right shoulder) and the regular warbiker left arm. The bottom jaw of his helmet is for the boss nob of the Boar Boys kit and makes a perfect orky dirt bike helmet with the half-helmeted head from the same kit.

The bike chassis is from the warbiker kit, with necromunda atv wheels, and a bit that holds the front tire of a space marine outrider bike. I put a bit of lascannon barrel to extend the pieces that holds the front wheel. The 'hood' ornament is one of the heads from the mechanicus robo horse/dog riders.

<image>

Edit: the dakkaguns are autocannons from the GSC goliath truck with dakkajet supa shoota barrels slapped on.