What is the stock hp at the rear wheel on...

12 replies to this topic

Posted April 21, 2003 - 12:09 PM


What is the stock hp on the wr 450?

  • RunAnywhere

Posted April 21, 2003 - 12:21 PM


My title shows 59 as the rated hp. That is before the uncorking. It did seem a bit more mild than that completly stock, though.


  • Beta_Man

Posted April 21, 2003 - 12:28 PM


I had my yz 426 on a dyno which was stock except that the head was shaved and polished. It hit just over 40 hp. My brother also had his cr 500 on the dyno and his bike was ported and polished and piped it hit 45 hp. The dyno i was on NRA dyno so it was rating them a little lower then what they acutally would be by about 8 hp or so. :) I can wait to get my 450 on it.

  • Indy_WR450

Posted April 21, 2003 - 02:37 PM


It depends on your pipe and air box intake mods. 40 - 45 HP should be right on a dyno. I cant remember what the number was in Dirt Bike magazine but they had a 450 four stroke shoot out this month with dyno results chart and the KTM had the most HP everywhere. The mag is out in the car. Pick up a copy and see why we all screwed up and should be riding orange! :)

  • Chas_M

Posted April 21, 2003 - 07:42 PM


Re: Dirt Bike test dyno figures. I have a hard time believing that a stock KTM 450 has such a dominant HP advantage over an uncorked WR450 throughout the entire powerband. Either the KTM tested was a ringer or the WR450 was a dud. Over 46 HP from a stock KTM 450 is unlikely. I suspect some skulduggery here, like perhaps KTM slipped in a 525 in place of the 450!?

  • SFO

Posted April 21, 2003 - 07:55 PM


here is a stock yz-426 VS, a 2mm big bore with a pipe and some rubbing.
BTW, this is mostly just rubbing. 444.htm

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  • galant2nr

Posted April 22, 2003 - 05:58 AM


Maybe it's lingo I don't know, but what is "Rubbing"?

  • sjw

Posted April 22, 2003 - 07:36 AM


for the price of a 450 ktm and parts availabilty and leaky fork seals the felt sorry for the orange machine!

  • SFO

Posted April 22, 2003 - 07:44 AM


I took a special class to learn rubbing.

  • galant2nr

Posted April 22, 2003 - 08:03 AM


That is great, but what does it mean? Porting? :)

  • beezer

Posted April 22, 2003 - 08:20 AM


In San Fransisco I thought it was taught in kindergarten along with Heather Has 2 Mommies.

  • SBG

Posted April 22, 2003 - 04:04 PM


My guess is he means the engine was massaged. Basically a lot of cleaning up/blue printing of the stock engine and cleaning up all the things that aren't done in production. I guess? :)

  • SFO

Posted April 22, 2003 - 05:18 PM


I recut the seats boring the throats at 75 degrees with a .030" seat width and the chambers were opened up, ie unshrouded. The seat port transitions where smoothed too and I clipped the protruding valve guides off on the intakes. More of the details are on the first page of the dyno stuff,

The piston was also lightened on the backside to within 6grams of stock.
This was completed over a year ago and totaly thrashed in 1400miles of my baja honeymoon, but it didn't break.
I am now rebuilding it with a fresh gearbox and a long rod/stroker to bring it out to around 470cc.
I'll also use the hotcams intake with a new yz exhaust cam.
KMPI ss valves will replace the wilted ti stockers.
Thats about it... :)


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