yz pipe on a wr

[hoggernaut]

I have a 07 wr450, with all of the free mods and the ais removed. My buddy has a 07 yz 450. He has an aftermarket pipe, so his stock is available. Just wondering if anyone has any experience with this. What kind of performance gain could i expect? Thanks

[GuyGraham]

Its supposed to be better than the stock WR pipe because of the bigger dia header

I'm gonna go down the YZF pipe route for my 08, as the aftermarket stuff is too rich for me

[knighty]

I have an 08 WR450 and put a complete YZF system on it and loved it, I then spent many dollars on a yoshi system which I have just pulled of the bike and gone back to the YZF as it is better. YZF is also quiter which i prefer! Do it!

[tech24]

I think it will be an upgrade. I believe the 2 engines are the same except trans and cam timing so should help bring it to life. Don't for get about the free cam timing mod unless you have done it already.

[knighty]

what is the "free " cam timing mod?

I see many threads re post 06 changing inlet cam timing but 07/08?

the 07/08 have different inlets and exh cams to the YZ

[tech24]

Im not sure if it applies to all years but the intake cam is retarded 1 tooth from the yzs just need to advance it one tooth for instant free power. I thought the newer ones were the same but maybe not.

[ASternad]

09 WR450 Here, with a 09 Header and muff.

Lost some weight and gained more usable power throughout.

Stock YZF was too loud and no sparky, so I installed a PMB end cap.

Very happy with the results.

Oh yeah - no free cam timing mod for 07-09, just swappable cams with YZF's.

[tech24]

09 WR450 Here, with a 09 Header and muff.

Lost some weight and gained more usable power throughout.

Stock YZF was too loud and no sparky, so I installed a PMB end cap.

Very happy with the results.

Oh yeah - no free cam timing mod for 07-09, just swappable cams with YZF's.

Well good to know I thought my buddy with an '09 wr said he did timing mod maybe he said he was going to so I'll guess I'll inform him he can't. Thanks for the info.

[SXP]

I'm running an 07 YZ pipe on my 07 WR - pretty impressive power gains. If he's not giving you the header also, then just transfer the donut gasket from the WR pipe to the YZ pipe so you can use the stock WR header.

[GuyGraham]

I'm running an 07 YZ pipe on my 07 WR - pretty impressive power gains. If he's not giving you the header also, then just transfer the donut gasket from the WR pipe to the YZ pipe so you can use the stock WR header.

Its the header you need for the power

[WR450FGreg]

.

I have both '08 YZ450F (Powerbomb) and '09 (non-Powerbomb) systems available here for my '08 WR450F.

I have tried both headers and can't split the performance between the two. They both improve bottom-end and midrange punch after re-jetting according to my seat-of-the-pants dyno.

As far as mufflers go, I haven't bothered to use either of them. (Ones a huge big thing and the other's a "shorty".)

I have modified my stock WR muffler to maximise the gas-flow so I don't see the need to use either of the YZ ones.

There's a lot of great info about it all here: https://www.thumpertalk.com/forum/showthread.php?t=349760&highlight=Modified+Muffler+saves+big+%24%24%24%24

[guns and hoses]

Does anyone know if i can put my old hindle exaust from a crf 250 on a 07 wr 450

[JSanfilippo]

Its the header you need for the power

Both are good for some gains individually, but you'll need both for the max gains.

Does anyone know if i can put my old hindle exaust from a crf 250 on a 07 wr 450

No. At least not without some serious hacking and welding.

[snaggletooth]

I did the YZ pipe swap and added the PMB sparky cap. My factory pipe was smashed after a hard crash. Best free up-grade yet! I'm sure I could reap a liitle more HP than just bolting it on if I re-jetted. Now its running a little lean. I'll leave it as is, I hate messing with that !@#$% carb!

PS, Polish the YZ can before you mount it!