As far as thumpers are concerned the Honda XR has a history of being a beast with bags of torque. 

Lets say we are not disappointed with Nat's XR600. This was a ground up build of a 1996 model with long range Safari tank and all the gear you would want for crossing the Great Sandy Desert. We stripped the bike down to it's bare bones, fabricated a new subframe, repaired some stress fractures and gave her a fresh coat of satin black powder coat. The tank is from a CB250 with some tunnel modifications to help it fit the XR frame. The 17' SM Pro wheels are laced to Talon hubs with custom stainless spokes and wear a set of Shinko 705's. A Mikuni flat side gives the engine some extra urgency and the stainless pipe lets everyone know you are coming through. The front end was lowered via slipping the forks through and modifying the preload spacers. A blast to ride X ON is not your average chook chaser.