New to Thumper Talk

Just got an '03 WR450f a few weeks ago and have got so much help from the members on Thumper Talk. Just joined the forums tonight so I could search the posts. I am trying to figure out how to know if the restrictor plate has been removed from my air box. I need to know so that I can select the correct jet to install. Am I just supposed to remove the plastic that is between the two ports that go down toward the air filter? Thanks in advance for any help you can offer.

Okay, I think I figured it out. I went ahead and pulled out the whole plastic piece with the two snorkels that go down toward the AF. I will go ahead and jet accordingly. The new "performance" jet kit from Dynojet says to use #138 and then add +8 (#146) without the restrictor plate. Weird thing is, the stock jet was #160.

You should avoid the dynojet kits if possible.'

Lots of poorly made jets are in those kits, making tuning a pain.


JD Jetting or follow the pinned posts at the top of the forum.


The stock jetting on a WR is not a 160, so someone already changed it.

It's the pilot, needle, exhaust, intake that need to be addressed AT THE SAME TIME.

You can;t just fix one part of the puzzle and expect positive results.

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