We pumped up a KTM 150SX to compete with the 250Fs,
not run like the 250Fs. This hard-hitting, turbulent powerband
gets the job done, although it is best in the hands of a skilled
tom and made the 150SX engine feel entirely different. It
had a quicker response and lit the world on fire (for a short
time). The increase in power made the overall powerband
feel shorter than in stock trim. It was a handful—extremely
powerful but hard to keep in the meat of the powerband.
Luckily, we have some experience with short KTM powerbands and started fine-tuning the power-valve adjuster. We
went in a full turn and, as with the air-screw change, this
brought the entire powerband around to our liking.
The power-valve adjustment broadened the powerband,
making the 150SX much easier to ride. The power ramped
up slower, hit harder in the midrange and had a good pull
to the top (albeit without much over-rev). It didn’t fall on
its face like it did in stock trim, and we knew that small
turns of the power-valve adjuster could give or take away
bottom and midrange power in a heartbeat.
Most motocross racers have spent years trying to come
to terms with the unique feel of air forks. It is an adapta-