Two-wheel-drive motorcycle

The Honda CRF450X is a pretty good motorcycle straight out of the box. Every time it’s been entered in the Baja races, it’s won its class—and Honda has pitched it as “perhaps the best off-roader ever built.” But Philadelphia engineer Steve Christini reckons he can go one better. For $6895, he’ll sell you a CRF450X with a mechanical two-wheel-drive system that delivers power to the front wheel, using a series of chains and shafts. Even better, very little hp is lost: there are no energy-sapping hydraulics involved. According to Christini, “You can easily conquer the gnarliest hills, ruts, mud, roots,...