Dont know the horsepower rating but I do know the difference. Horsepower at the crank is pure engine power. It is horsepower measured at the crankshaft. Horsepower at the rear wheels is a true measure of rideable horsepower. It is measured of course at the rear wheels on a chassis dyno which is just 1 or two big rollers in the ground. the diffence is that the horsepower at the wheels is horsepower from the crank after it has been lessened by different mechanisms such as the transmission, sprockets, and chain. These mechanisms especially the transmission are not 100% efficient. This is why the horsepower at the wheels is less. Hope this clears it up.
2000 400EX, FMF Powercore IV, Dynojet kit, 14 tooth front sprocket.
MY 2001 400EX MAKES 27.3 HP AT THE REARHEEL WITH A YOSH FULLSYSTEM A K&N FILTER JETTED AND A XR250R REVBOX ........I INTEND ON PUTTING IN 440kit WITH CAM AND SOME HEADWORK...............PUSHIN FOR 40hp PLUS........
I paid the 50 bucks to have mine dynoed. I have 28.2 hp at the rear wheels. This is of course, with the chain, clutch and throttle adjusted properly. People don't understand how important this is. After I do all of my mods, the shop said they'd only charge me 10 bucks now. That's why i did it now so i can compare the differnce. I'm telling you guys, for a thousand bucks in mods to the 400ex in the motor, the Raptor doesn't look so good anymore. With the right mods, you can be at 42 hp for a thousand bucks. Ya gotta shop around.
