Yeah yeah, not motorcycles, but suitable two-wheel insanity:

Glacier Bike Downhill Saas Fee 2012

Watch large for a better appreciation.

Holy shit! That looks awesome....where do I sign up?  I have to say our rider was a little slow on the sprint, but made up some ground on the downhill sections.  He must be packing a few more lbs than the others.

Wow, that was wild ! Adrenalin pumping stuff all the way down !

that was a long way down.