WR426 Horsepower

6 replies to this topic
  • Scuba_Steve

Posted April 17, 2002 - 06:57 PM


Curious about the horsepower the 426 makes. Mine is mostly stock (gray wire cut, throttle stop cut, airbox cover removed, exhaust baffle removed) and I want to know it's horsepower. Does anyone know? Also, does anyone have information on the HP increase with YZ cam timing?

  • SFO

Posted April 18, 2002 - 04:47 AM


I believe someone posted that a derestricted wr will make 42 rwhp on a dynojet dyno.
No idea what the hp difference is for yz timing.

  • jamracing

Posted April 18, 2002 - 04:55 AM


I'll be dyno'ing mine with the Supermoto rear wheel (you can't run a knobby on a dyno). Will let you guys know. Should be interesting, since it has the Big Gun pipe, YZ timing, and the 2 stroke airbox...

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  • SFO

Posted April 18, 2002 - 09:15 PM


With my big bore kit, cams, and Arrow pipe my wr made 54 rwhp on a Dynojet dyno with nu-tec fuel.

Hey Jam, whats the airbox you are ryunning? Pictures links whassup?

[ April 18, 2002: Message edited by: SFO ]

  • Scuba_Steve

Posted April 18, 2002 - 03:56 PM


Thanks all. Jam, I'd love to hear the results you get.

  • jamracing

Posted April 19, 2002 - 04:55 AM


The airbox is from the 2-stroke YZ250. It is bigger in volume, so there is more still air to be pulled in. The rubber boot stays from the WR. I'll have pix (and hopefuly results) next week.

  • wintrick426

Posted July 11, 2008 - 07:51 AM


i'm new here.
i 'm the owner of a nice wr426sm.
the only mod my bike has is the trotle stop, the grey wire is still intact and the cam olso, my airbox uperlid is off.
and just got my bike back from a dyno test and the test shows 48.5 hp @ 8635.4 rpm
i have the standard front exhaust pipe and a doma demper.
is that nice or is that the afridge hp of a wr426


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