2007 Ski-Doo Summit X 151 800R Power T.E.K., 2007 SKI-DOO SUMMIT X 151 IN GREAT SHAPE! 2019 TABS ON IT! Most significant for 2007 is the major addition of a more powerful Rotax 2-TEC 800R PowerT.E.K. lightweight two-stroke. All Summit 800s have this engine, and only Summits get it (no MX Zs, yet). New from the ground up, the 800R is the highest-tech carbureted two-stroke ever, fitted with PowerTEK engine management for automatic calibration and excellent fuel economy with a full complement of features, such as throttle position sensor, knock sensor, ambient temperature sensor, crank position sensor, liquid-cooled crankcase, new 3-D R.A.V.E. valves and more. The “800R” is said to the most powerful engine in both the 800cc and 900cc classes with 151 horsepower (see dyno test in this issue). Cutting-edge electronics and exhaust controls enable it to exceed the U.S. EPA emission standards while remaining lightweight AND carbureted. Sweet.Overall, the Summits are well engineered lightweight deep snow machines. They float well for their track lengths, but the rider-forward positioning requires some adjustment in how the machine behaves. The 800R is so good, only the heavy guys, steep freaks and those simply addicted to having the biggest will need a 1000. Remember, power to weight ratio the lighter sled with the best ratio wins. Running quality and consistency, as well as fuel economy, are as good as it gets with fully-automatic electronic engine management, including fuel delivery.