From the April 2007 Dirt Rider Magazine: Although it looks like an SX model, with handguards and a headlight, closer inspection reveals an all-new motor! Mated to the latest generation bottom end, now with electric start, the top end is a single-cam design like all the former SX models (pre-2007 450/525) and current EXC/XC bikes. Expect a weight reduction and a higher power output. The water pump is now located on the case instead of off the camshaft. We suspect the transmission will continue to be a six-speed. When will we see it? Not sure, as KTM wouldn't comment on the bike but did mention that any homologation in the U.S. is a timely process. Could be '08 or '09. Although the DOHC KTM is using is proving to be very reliable I'm not real suprised at with the use of a SOHC on the off-road bikes. What does suprise me is their (DR Mag) expectation of more power from a single cam. I'm no engine designer/builder but I'm pretty sure that a DOHC will always have more HP potential than a SOHC.