Have four-strokes closed the gap?
The rules are a mess. Back in the two-stroke days, someone decided that four-strokes needed a displacement advantage
to be competitive. Those days are long
gone, but the skeleton of that old set of
rules remains, and there’s no consistency
from one club to another. Some rules have
144cc two-strokes racing against 250cc
four-strokes, others have 250s against
250s, and other clubs just don’t care
because there are so few two-strokes on
the start line.
Here’s what will happen: the distinction between two-
stroke and four-stroke will eventually wither away. It’s
already happening in the amateur racing world, and for
the first time in years, the two-stroke market is showing
signs of life. Both Yamaha and KTM remain committed
to the two-stroke and continue with year-to-year model
updates. Beyond that, KTM reports that two-strokes are
its biggest sellers, although primarily off-road bikes.
That’s why we’re here. We took the two most current
250cc two-strokes on the market, the KTM 250SX and
the Yamaha YZ250, and compared them to the top bike
in the 250 four-stroke world, the Honda CRF250R. We
already know that the CRF will demolish a 125 two-stroke. We already know the CRF has an edge on a
144cc two-stroke as well. But those rules are going,
going, gone. In a straight-up battle of 250s, does the
more current technology of the 250F trump the power
advantage of the 250 two-stroke?
KTM has continued to develop the two-stroke all this
time, getting lighter and more powerful every year. The
250SX isn’t a huge seller, but it benefits from the development of the monstrously popular 300 off-road bike.
The 2009 SX already had a great motor, and KTM left it
alone with its case reed motor. The suspension got
much more significant changes, starting with a
redesigned WP shock. The bike has no shock linkage,
instead relying on progressive damping to stiffen things
up before bottom. Now that system uses a longer needle to do its job as well as a revamped bottoming system. The fork has new tubes with different flex characteristics.
The survivor: The Yamaha YZ250 weighs 217 pounds and
sells for $6599.
DB OLD WORLD VS NEW TECHNOLOGY