YZ Exhaust in the forest

I've got a 09 YZ header/muffler coming for my 09 WR450.

I'm thinking of trying the Yamaha GYTR® Quiet Muffler One-Piece End Cap and Spark arrestor, for sound and compliance reasons.

Any one try these bolt on's, any power loss or delivery changes noted?



I use one of these on an 08 YZ exhaust.


No loss in performance to speak of with the spark arrestor.

About same noise as stock too.

I had to add the silent insert to just pass 96db. Maybe a small power loss, seemed to smooth out the mid and add a little overev.

So with both parts it's a little pricey, about $150 all in but it works good.

If you're worried about looks mine completely disclored grey within a couple months. I don't know if this is common but I've heard of it happening to others.

Mine when new


The blue part went gray?

How is bottom end torque over stock with this setup?

The blue part went gray?

How is bottom end torque over stock with this setup?


Heaps more torque of the bottom and mid with this setup compare to uncorked WR exhaust.

It makes it a whole different bike :thumbsup:


This WR450 feels like it's being held back, even with all the free mod's.

It's weird, it's like it stops revving at a certain point. My 05 KTM exc will pull any gear (except 1st) to the moon.

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