WR exhaust

11 replies to this topic
  • Bryce

Posted April 20, 2003 - 05:33 PM


Does anyone know if a stock YZ 426 exhaust will fit the WR 426? If so, would there be any problems with the jetting? Or would the jetting be similar to, say, an FMF silencer?

  • Paul_Hindle

Posted April 20, 2003 - 09:01 PM


Yes it does fit, but will have to alter jetting as you will probally be running lean.

  • DesertChris

Posted April 21, 2003 - 09:14 AM


You will have to pick up maybe four parts from the dealer depending of what you got with the YZ can (the rubber collar, damper, washer, and bolt).

16 bolt $1.08 95817-08030-00
17 washer $0.75 90201-081R9-00
19 collar $6.20 90387-0814J-00
18 damper $2.61 5BE-14714-00-00

There really isn't much flow difference between the uncorked WR and stock YZ cans. I was already running the YZ jetting before I swapped and didn't notice a difference after. The muffler swap is mostly a weight issue, that is the noticable difference.

  • Bryce

Posted April 21, 2003 - 03:55 PM


I'm not too worried about the weight issue, I'm 275, so I doubt I will notice the pound or two difference.
I bought the pipe because I had already purchased an FMF power core 4, then I found out it doesn't just "slip on" it's another $150 for the header, so I picked up the YZ can for a song, should I go ahead and pay for the header, or is it a waste of money (the YZ will do??)
It was already jetted for the FMF, which I didn't install, but the WR is uncorked, and there are gobs more power, but it pops a little when I let off the throttle.
Just looking for opinions, there seems to be some wise ones around here. Thanks :)


Posted April 21, 2003 - 06:07 PM


I swapped my wr pipe for a yz pipe and the bike ran much stronger. The nearly four pounds difference in weight IS noticeable because it is all carried high on the bike. I did not need to rejet (at 2000 ft) but am using a PMB spark arrestor with a silent insert so the restriction was somewhat similar to the vortip I used with the WR pipe.

  • Junior_Vet

Posted April 21, 2003 - 06:11 PM


Didn't your PC4 come with a reduction spacer? The PC4 I got a few weeks came with that and it slipped right on my stock header pipe. It should be the same for the 450. Perhaps the spacer was missing from your kit? :)

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  • Sylvain

Posted April 22, 2003 - 03:34 AM


Talk about timing ! :D

I intend to install a YZ pipe model 2001 on my canadian wr 426 2002, and I was wondering about the same things.

Will it fit right on ?
What are the parts needed ?
What changes will have to be made to the jetting ?

And finally, the canadian WR pipe is welded a the end, we can't just uncorke it. The opening is about the size of a quarter.

What difference will the YZ pipe bring :D?
Will I lose low rpm torque :D?
What else :)?



Posted April 22, 2003 - 05:26 AM


Uncorking it brings more power everywhere, including low-end torque. My change-over was an easy bolt-on - and as I mentioned before no jetting changes were necessary - I still run stock jetting. The toughest part is the slip-fit gasket - you need to be careful not to damage it too badly during the exchange. My wr is an 02, the yz pipe was an 01.

  • Sylvain

Posted April 22, 2003 - 06:07 AM


It seems that you have exactly the set up I'm looking for. :)
When you say that you installed a PMB spark arrestor with a silent insert . Where did you get this ?


  • Bryce

Posted April 22, 2003 - 06:46 AM


I purchased my PC 4 at the FMF factory in Compton, it was at their 'scratch, dent, and ding' sale. It was just the slip on with no accessories, and the salesman told me that it should slip right on (typical salesman)
I went to get it installed and jetted at Chaparral, and they told me about the different size, so I picked up the YZ can.

  • Junior_Vet

Posted April 22, 2003 - 07:39 AM


The YZ silencer will be quieter than the PC4 any way. Good move.


Posted April 22, 2003 - 07:53 AM


Pro Moto Billet - I don't have their phone number handy but they advertise on TT :)


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