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What is "crank horsepower" my bike has 36 and it's an 08 crf250r, but at a dealership they said a 2014 rmz 450 had 59.7 crank horsepower and I know it's gonna have more then my bike but there's no way it's that much

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There are 2 standard ways to measure horsepower... The best know is a dyno, which will measure the HP at the rear wheel. But engine manufactures have a machine that will hook directly to the engine and is measuring the HP at the end of the crankshaft. The Hp measured at the crankshaft is going to be much higher than HP measured at the rear tire. The transmission and final drive loose a significant amount of power from the engine. On a high performance car the wheel HP is usual 80-90% of the crank HP.

 

I wouldn't be surprised if the new 450's put out 59HP. They have nearly double the displacement so i would expect close to double the power. In 2008 most 450's were at least hitting the 50HP mark, I think the kx450f has 52HP that year. 

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What is "crank horsepower" my bike has 36 and it's an 08 crf250r, but at a dealership they said a 2014 rmz 450 had 59.7 crank horsepower and I know it's gonna have more then my bike but there's no way it's that much

That's just an another way of determining the power you're getting from your wheel (power through the trany, drive-shaft and tire wrinkle) as opposed to from the engine itself.  It all boils down to resistance. :devil:

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I don't believe the rmz has 59 but it's probably very close. Crank horsepower is how much power the engine makes right at the crankshaft. By time power makes it past the clutch, tranny and finally to the wheel, some of it is lost which is why wheel hp is always less than crank hp.

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What is "crank horsepower" my bike has 36 and it's an 08 crf250r, but at a dealership they said a 2014 rmz 450 had 59.7 crank horsepower and I know it's gonna have more then my bike but there's no way it's that much

 

 

That's called "Brochure Horsepower", not to be confused with the actual motive force your tire puts to the ground.

 

The 2014 RMZ450 makes approximately 53 RWHP.

 

2014-RMZ450-DYNO-RESULTS.jpg

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