Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/103759
RACE RIDDEN P62 2012 KTM XC-Ws use a special aluminum alloy with high ductility that is less prone to cracking from impacts. To reduce overall size, the motor now uses one oil circuit instead of two separate circuits. Filtering has been improved as well. Just about every part inside the motor is lighter and smaller, including many moving parts. KTM claims there is a 15 percent reduction in oscillating mass with the 450 and 20% less with the 500, and this translates into a lighter-feeling machine on the trail. Much of the overall concept of the motor is the same. It's still a single cam, and most of the components in the valve-train are the same - however the head is quite different to accommodate the FI system. The clutch, perhaps a weak point on the previous motor, has been completely redone. It's smaller, stronger and uses a KTM off-road two-strokes are getting more like four-strokes... 54-63 KTM XCW.indd 62 single diaphragm spring instead of four coil springs. Transmission is a six-speed. All of the four-stroke models have new mufflers with spark arrestors and are green-sticker legal. As for the chassis, all of the four-stroke Ws get the same trimmer and lighter chassis that debuted last year on the 250 and 300 XC two-strokes, including the latest WP PDS rear suspension system and reworked WP fork. The new frame has a more central shock mount and is positioned to where the rider feels less bump impact through the frame. While still delivering tons of power overall, the new 450 has an extremely smooth and manageable power delivery, and it has tons of useable bottom-end. This bike chugs extremely well off the bottom and seems resistant to stalling. If you're not into shifting, this bike might be for you. I found that on the tight trails of Wyoming, you could simply leave this bike in third gear and go. It "carburates" extremely well and throttle response is crisp, making the 450 remarkably easy to ride in the tight stuff. While this bike is far more single-track-friendly than before, it still revs well on top and hauls like a 450 should on more open trails. Even though the 450 weighs about the same as before, it feels much lighter on the trail, which has a lot do with having less oscillating mass and the more streamlined chasses. But the bike still weighs right around the 245-pound mark, which is about 20 pounds more than the 250 and 300 two-strokes. Even though the 450 feels lighter, you still know you're riding a 450. KTM added a cooling fan behind the radiator, which explains why the 450 (and 500, for that matter) did not turn into a geyser …and KTM's four-strokes are getting more like two-strokes. 7/15/11 12:49 PM