my review of the power now valve

The power now valve what’s it supposed to do? This valve is supposed to increase intake velocity thus increasing power to ½ throttle opening. In short, the power now is claimed to increase low end power. I got the power now valve and a long allen wrench shipped together. The long allen wrench also has a “ball” end to make the angle usage easier. The fit and finish of the power now were good; it is a piece of billet aluminum and the machine work looks top notch. I put the valve on at the track. It was reported that you could put this on in 10 min. maybe “you’ can, but I didn’t. The angle on the inside allen screw is kind of hard to get at. I was able to get it off easier than putting it back on. It’s not rocket science, but it is a hard reach thingy. Frustration took over and I mashed the air boot all the way against the box and was finally able to get a better angle on the inside allen screw. Presto change o , it went on. The test mule for this ride was the infamous “death from above 426”. This is an 01 wr 426 with yz mods on it. It has yz plastic with odo and light removed, 52 tooth talon groovelite rear sprocket, yz jetting, bk mod, white brothers “s” bend R4 exhaust, yz tank and seat, with a full blown MX tech suspension. The initial ride was somewhat uneventful. I mostly was looking for a loss on the top end and found none, but I wasn’t “feeling” the big low end boost I was looking for. I went back to the pits and realized the reason I didn’t feel anything different was because I was riding my 426 the same way as always. I figured I’d really try to bog this thing next time out; also I wanted to see if I could increase the squirt duration on the bk mod without any bog. I was able to increase the squirt by about 1/8 of a turn (1/8 of a turn is significant with this mod) without bog. This was good. I went back out with the expressed task of bogging the bike by shifting way short. I came rolling out of a corner in 2d, up shifted way too soon, and whacked the throttle about ½ open. I expected the usual “waaaaaaaahhhh” as it built revs, what I got was most unexpected. I got the “waaahhh” but the front end came up, the rear end broke loose and I started “going” a lot harder, a lil’ sideways I might add. The bike had a whole new “punch’ in the low rpms. This was nice. Then I went off to a stair stepped hill of about 5 “steps” of about 3’ to 4’ in height , with the lead up on some of these at about 15’. I had been going up this hill in second, this time I went for 3d gear. I rolled the bike around in 2d, straightened it out and immediately up shifted to 3d. I had about 10’ to the first 3 footer, I wasn’t too confident, but I figured this being a step up, not much bad could happen. I was pleasantly surprised. The bike took hold, shooting me up and accelerating all the way up the hill, revving out. This too was nice. I made a couple more runs like that ,then for giggles I tried up shifting to 4 about ½ way up, again way sooner than I would ordinarily with very little space for the bike to rev before hitting the step face. Woo-ie! The bike took off, fast. I was taken back a bit and because of my shock I allowed the bike to pick up more speed than I am comfortable with. That was that for any more 4th gear shenanigans on the step ups. This mod, the power now valve has opened up a whole new range of usable power on my bike. To find the new power ya gotta lug it more than you would ordinarily. The word from Dave Simon is you can carry a lower gear out of corners, etc. I found you could. The SITREP. The power now is about 70$ . I like it. It does appear to build power down low. The bike starts quicker, first kick usually, and Dave said that 250fs’ don’t have to use the hot start with this installed. It has opened up a whole new “power band” on my bike. I will be taking a spare power now with me to my next big ride and have some other 426 and 250f riders give it a try. This is a 70$ well spent. I would recommend it. You can find out more info and how to order at

Think she could pull third gear starts now?! :)

It sounds really good, waitin for a DRZ review. Hey, maybe it'll get rid of my "bog". :D

she can..doubt the rider can tho :)

Compliments to you on some pretty good testing. I've been kinda watching for powernow responses. Did you post your findings on the other boards? I don't recall if it was the YZF side or the boy's in Red, but they were draging the owner of powernow through the coals without any of-em ever trying it.


how much did power now pay you to write this review.let me guess they gave you free power now as payment.will you be giving review on the thunderalley pipe nect week?

Very interesting!...Dirt Bike mag (May issue) did install a "Power now valve" on a WR426 mod with apparent success. I want to try fabricating one of my own to fit in the stock flange. Seems easy enough...

[ June 13, 2002: Message edited by: dominator426 ]

ha!freestyle, power now pay me? heck no, the just gave me a factory ride in the 03 supercross season. :D actually i went out on a limb on this one. i kinda figured it would work so i bought 2, one for a birthday present. but hey, if it didn't work i'd just send 'em back. btw, if yamaha usa wants to send me a yz450, heck i'd test it. :)

The dyno test at would have been done at wide open throttle, so the "Power valve Now" seems to enhance flow at any throttle opening or any RPM...Have you noticed more improvement under half throttle than you did over half throttle? Is there a power surge when the second half starts opening and admiting all that air from the top half?

[ June 13, 2002: Message edited by: dominator426 ]

Power now Picture

Click that baby it shows the pic on the webiste you just have to go thru the stor section to get to it.

dominator, i didn't notice any power surge in that transition area.

Install power now on my 02 WR426. Try to make it stall counld not do it, without locking the rear brake. Power seem good down low. Need to try it out on a full days ride. Rode around the yard only. Did get the bike hot. Started without hot start button. This never happen before. T-4 on the for next test

i want to strap a dyno machine to my @ss then test bike while i race around kiddie track.they just added a 3ft.double and i want to make sure bike has enough hp before i attempt to clear it.i saw a kid riding z50 come up short on it. knocked the bubble gum right out of his pockets.i finally have a chance to beat some of these kids.especially if i dont have to roll the doubles anymore.

How about posting a picture of this animal....There web site doesn't even show a photo. Skunkworks Item I guess...

Bonzai :)

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