9 replies to this topic
  • YZ400FPower

Posted July 22, 2004 - 03:48 PM


Hey guys,
I was just wondering the horespower numbers for the 1999 YZ400F :thumbsup: , the 2000-2002 YZ426F :devil: , and the new 450 :awww:. Just wondering.

Thanks :lol: :D

  • stainlessTT

Posted July 22, 2004 - 04:01 PM


Yeah I wanna know about the 04' 450 too


Posted July 22, 2004 - 04:47 PM


id like to know about the 426's. id like to know what my '00 yz426 is making right now, before i bore and stroke it(488cc).

  • YZ400FPower

Posted July 22, 2004 - 06:40 PM


It would be kinda cool if someone could tell us. I hope that my 1999 YZ400F is above 40hp :thumbsup: with my exhast, uni filter, and top of airbox.??????? :devil:

  • Jeffro426

Posted July 22, 2004 - 06:41 PM


All the 400 series yamahas have made in the 47-50 HP range...they just seemed to refine and make them more smooth along the road.

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  • Satch0922

Posted July 23, 2004 - 02:20 AM


2001 YAMAHA YZ426F
Still the king after all this time. The 426 is still powerful, but its strongest points are suspension and handling. The clutch works better for 2001 and there’s less of a carburetion hitch if you whack open the throttle too fast.
PEAK HORSEPOWER: 47.0 @ 9600 rpm

  • chrome-crf

Posted July 23, 2004 - 06:08 AM


The 400 is 43hp...........426 is 47hp..........450 is 50.

  • YZDAD1

Posted July 23, 2004 - 06:32 AM



  • Rich_Rohrich

Posted July 23, 2004 - 08:19 AM


Here are a few dyno runs from my website:

This compares Jon Escombe's ’00 YZF 426 and the YZF444 that SFO built. They were run on different dynos but it's still an interesting comparison.
http://www.four-stro...ne_yzf_ 444.htm

Here's some additional runs with SFO's bike:

and some more info from Jon's tuning:


  • YZ426FPilot

Posted July 23, 2004 - 10:07 AM


The 400 is 43hp...........426 is 47hp..........450 is 50. :

Thats approximate rear wheel HP where it all counts. If you want to get all excited over numbers look at the SAE values: :thumbsup:

YZ400- 54 YZ426 -57(00)-58(01-02) YZ450-60

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