2012 Husaberg TE 300
Theoretically, two-strokes are superior to four-strokes. With a combustion cycle every revolution instead of every other, they make power twice as often. Which is why, in racing, four-strokes are routinely given as much as a 200 percent displacement advantage.
Nonetheless, there are solid arguments against two-strokes. Environmental, for one, as two-strokes run on a mixture of gas and oil that makes for smoky exhaust emissions. And economical, in that it makes little sense for a manufacturer to spend money developing a two-stroke engine in this four-stroke era. That’s what doomed MotoGP two-strokes at the start of this century.
2012 KTM 125 SX
In the dirtbike world, however, there has been a bit of a backlash lately, as an increasing number of riders have been returning to two-strokes. Why? Lighter weight and snappier throttle response, for starters, but perhaps more importantly, reduced cost of ownership. Not only are two-strokes less expensive to manufacturer and thus purchase due to their having fewer moving parts, they’re also cheaper to maintain—there’s no labor-intensive valve train to look after, and a new top end costs just a few hundred dollars compared to a few thousand. Proof of this trend can be seen in the success of KTM’s 300 XC-W enduro, which after being fitted with an electric starter became one of the Austrian firm’s best-selling models.
For 2012 KTM has turned its attention to its two-stroke motocrossers, giving them an all-new chromoly-steel frame with the same cast-aluminum swingarm and progressive-linkage suspension that debuted on the category-busting 2011 350 SX-F. While they were at it, they brought back the 125 SX, which joins the 150 SX that had briefly replaced it in the lineup along with the 250 SX.
Meanwhile, KTM-owned Husaberg, which recently earned accolades with its high-tech, horizontal-cylindered four-strokes, has itself added two new two-strokes. The electric-start TE 250 and TE 300 are based on KTM’s link-less off-road models, with engines retuned for torque plus two-position ignition-map select switches and wide-ratio, six-speed transmissions.
Looks like we’ll have to start marking one gas can “pre-mix” like we used to…