Using hinges and half pipes I was able to hold flaming balls in place. This allows my motor bike to roll around on them while also providing heat to turn the water cannons into steam power.
Hold  until the middle section raises just off the ground, you can use  to go back down.
Arrow keys to control, hold both the directional keys to boost forward. no room for a reverse.
Link to besiege downloads page: http://www.besiegedownloads.com/machine.php?id=20959