07 wr 450

Can anyone tell me if a stock yz 450f muffler will fit on a stock wr 450 header or do i need a yz header? Thanx for your help.


Can't comment on USA models (I'm in Australia), but I have fiddled around with 08/09 YZ450 and WR450 exhausts and it seems anything will fit anything.

The only hassle is the seal between the two.

I've had to unwrap the seals partially and use high temperature silicon sealant to make them fit properly at times.

Some combinations might require a thicker seal.

Go for it!


I have a stock YZ450 06 muffler on my WR450 07 with stock header. The header is smaller but some muffler tape wrapped around the header has sealed it fine.

I have a YZ450 08 header on its way... i'm pretty sure that will fit!

Again, its an Aussie bike, not sure about the US ones....

Different header diameter's but you can make it work

Best call is to go for the complete YZ system, you can get them cheap enough on ebay :p


I have a YZ450 08 header on its way... i'm pretty sure that will fit!

Yes, it fits.

I've tried on my '08 WR450F:

'08 YZ450 header

'09 YZ450 powerbomb header

I've got the complete systems here but never bothered to try the mufflers due to fears about increased noise, especially with the "shorty" YZ item. The '09 muffler is actually bigger than the WR450F one!

I opened my stock WR450F muffler up to 38mm diameter (from memory) right the way through to match the '08 YZ450F header. I believe it has now got much better flow efficiency than any other OEM muffler, be it WR or YZ.



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