08 wr 450

I have just bought a new 08 wr450 and have been researching how to get more power out of it. I know about the yz throttle stop, the grey wire, removing the exhaust baffle, and i don't have the AIS. My question is do I have to rejet the carb with these three mods, and if so, can someone recommend which jet or kit to use? Thanks.

I have just bought a new 08 wr450 and have been researching how to get more power out of it. I know about the yz throttle stop, the grey wire, removing the exhaust baffle, and i don't have the AIS. My question is do I have to rejet the carb with these three mods, and if so, can someone recommend which jet or kit to use? Thanks.

Here is what other people are running.:confused:

http://www.thumpertalk.com/forum/showthread.php?t=411240

Thanks. I should have also asked if I need to rejet before I ride if I complete the wire and exhaust baffle mods.?? All help would be greatly appreciated. This is my first thumper.

Wondering if there is a "good" answer to this?

Wondering if there is a "good" answer to this?

Have you reviewed what Indy_450 has provided in the attached link above? There are some "good" answers in their.:confused:

Indy_450? I meant good about mods without jetting.

The 07 and 08 WRs are Waaaayyyyyy too lean. Just bite the bullet and rejet...

Get the JD jetting kit.

Wondering if there is a "good" answer to this?

I still got my stock jetting on my 08WR. I do have the GYTR exhaust tip.. I’ve had the grey wire off. (I would not even think about removing the air box silencer without rejeting). I think these guys are right about the too lean thing. It runs a bit rough at sea level. And It runs much better at higher elevation.

But, the reason I don’t have my YZ throttle stop in yet, is that it’s just to tight for me to get at it. There is just no room for me. Maybe I got big hands or I’m not very good at building a ship in a bottle. If you can get it out, more power to you. I think I’m going to have to take the rear shock off, at the very least. So, for me, I’m going to do the jetting and the throttle stop at the same time..

Re-jet,open up the airbox all the way and put a pipe on it. It will be all the bike you'll ever need..Oh and I used the James Dean(JD) jetting and am very happy...gas milage could better though.

Thanks, btw, does anybody know the part number for the yz450 throttle screw?

Thanks, btw, does anybody know the part number for the yz450 throttle screw?

My GYTR AIS removal kit lists the part# as 5JG-14591-00

I have to change my previous statement. I was able to get the throttle screw out on an 08 without any dissasembly. I didn't even take the cover off. but will add that I couldn't do it with your standard allen key set.

we used a 5 inch long ball head allen socket, that was attached to a wobble extension, and attached to about 14 inches of extensions. we attacked it from the left side of the bike from behind the sub frame. one of the tricks is, with a flashlight, you can see the bolt, thru the frame next to the gas tank. so you are reaching it from under the bike, but looking at it from the side of the bike.

the wobble is key if you are using a ball end, becasue the screw head is not very deep and the ball end will skip if you don't push the ball end into the bolt while trying to turn it. I wasn't able to apply the force needed to keep the ball end engaged with a universail. so we used the wobble.

that flexible extension mentioned in the post above would work good, i think, as long as its not used with a ball end.

Ultimately, you should rejet, but Dirt Rider did test the bike with the free mods and stock jetting and said it wasn't bad, and of course it ran better at higher elevations.

Most will say JD is the way to go.

Getting at the carb is a pain, but like anything, time and patience will prevail. Loosen up the carb boots, raise the rear subframe, remove the rear shock, upper motor mounts and you should have all the access you need, aside from all the freaking hoses in the way! Doesn't hurt to remove hot start plunger, but be careful not to break the plastic threaded base. Aluminum pieces are available after market.

Read up around here on carb removal.

Hey everybody, thanks for all the advise and help. This thing RIPS. :excuseme: I have completed the grey wire, AIS, JT Jet, and throttle screw mods. I am waiting a little bit to do the muffler, and can't wait to see how much else this thing has. I havn't messed with the fuel screw yet, waiting to purchase a new one. There is an ever so slight bog when crawl to wide open, but I don't think that will be of any concern (don't plan on crawling in first gear). Once again THANKS!!:confused::excuseme:

a 50 leek jet helps that low end bog.., and I couldnot be happyer with my new aluminum, stainless Dr d full system.. wow.. check out qualitysmart.com

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now