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MountainMax

What is stock Horsepower on an 06 WR450? Compared to the 06 WZ450f ???

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Just wondering how much HP diff there is between these two bikes stock.

Also after doing the normal mods on the WR, does it come close to the HP of the yz..

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I have seen dyno runs in the mags of 49 - 50 for the YZ and the WR comes in 45 - 46.

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I have seen dyno runs in the mags of 49 - 50 for the YZ and the WR comes in 45 - 46.

A stock WR makes 37.0 HP @ 8610 RPM and 23.79 ft-lbs @ 7610 RPM

Testing was done at 60.0 F 33% humidity and 34.6 inHg As for a YZ I don't know how much Horse Power they make but I do believe it is somewhere around 50 HP. I also know that if you do all the free mods on the WR it does come in somewhere around 45 HP. Add a YZ cam, a GYTR pipe, and get it jetted right and you should come in right around your 50 HP mark with the WR

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WoW those free (well cheap) mods sure do ad alot more HP, But that brings another question, if the max HP and torque are at such a low RPM why do these bikes rev to 11000 RPM ? if they go past 8610 they will start to lose HP and torque?

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Yes you will loose power past the max horsepower RPM, the further past max horsepower you get the more power you loose. Every engine is different but all generally rev substantially higher then where there max horsepower is generated. This isn't a bad thing because it allows you to get in the meat of your power on your up shifts. I hate to do it, but I'm going to use a two-stoke term "Powerband". All motors have a powerband, your powerband is basically between max torque and max horsepower. It starts right about at max torque (always a lower rpm) and ends right about at max horsepower (always a higher rpm). The difference is in a two stroke the drop-off in power before and after your "powerband" is substantial, therefore the powerband is extremely noticeable. In a four stroke the torque and horsepower loss prior to and after the "powerband" is less. Thus causing you not to notice a distinct difference in power. This is the reason a four stoke will spend less time spinning and more time hooking up. I hope this helps. If anyone thinks I'm incorrect please feel free to debate with me.

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Thanks, that is a great explination, Im use to snowmobiles, they go to max HP and stay there cause of their CVT clutch, I can see how the bikes are different as they are manual shift, you rev higher so when you shift the rpms' wont be too low as to slow you down again cause youre not in the 'BAND'

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