New 03 Wr450 owner Questions

Hey guys, was wanting to ask you guys some easy questions. I just bought a slightly used 450 from a guy that rode it dead stock for 32 miles is all. Sould I rejet the bike to make it richer and what size jets do you suggest? Second, how do I remove the airbox snokel, and does anyone have any pics of other mods to the airbox? Third, do any of you guys run aftermarket T-clamps and how did you get the panel and all that wiring to mount up right to aftermarket t-clamps? Do you have some pics of your setup? I have protaper T-clamps w/ fatbars. I'm sure I'll think of some more questions later but that it for now.

You guys are a big help!!! :)

:busted:01 WR 250F (FOR SALE) Free mods, 03 cam (great!!), stock timing, stock exhaust, yz rear fender, ufo all blue plastic, pirrelli gar-cross rear tire, dunlop 739 front, ironman sprokets, did x-ring, homemade aluminum skidplate,BBR kick starter (like new), ims tank, sdg seat, twin air filter, enduro enginnering handgurads, seal savers, Fresh rebuilt motor!!!!

74’ XL250 (me and dads)

82 ‘XC430 Husky being restored

82’ WR250 Husky (dads trail bike)

83’ XR100

01’ TTR125L (Brothers ride)

4 stroke B Mid-South Hare Scrambles

4 Stroke C GNCC


Regarding the jetting, the guys will need to know where you're located and what elevation you normally ride. The WR450's have all come from the factory way too lean and rejetting is usually a must. You'll need to also verify what it's currently jetted at to see if the previous owner already jetted it for you.

There are plenty of pictures of the airbox mod out there. There are a few (slightly blurry) photos here: Airbox Mod and I have some better ones I could email you later.

I'm using the DH1 clamps that came with my GPR 2.0 dampner. It had the adapter to mount the WR wiring panel. It wasn't a perfect fit but it worked out. You can see photos here:DH1 clamp and GPR 2.0

Here's a photo of my airbox mod. It's pretty staight forward.


As far as jetting goes, my bike runs the best with stock jetting, I'm at sea level.


Got the Scotts upper t-clamp so I could mount my damper and pro-tapers... it comes with a bracket for the odo and the wiring bracket bolts to it just like stock. Looks super clean and no hassles.

I put a 162 MJ and a 48 PJ in and it works great after pulling the snorkel out and the rest of the free mods, no glitches anywhere in the carburetion.I didn't have to touch the needle, and I did install a Zip Ty fuel screw for my convenience. The stocker is a PITA to get at with the starter right there....

It's easy to pull the snorkel; unstrap the battery and flip it over out of the way, slip a couple screwdrivers between the snorkel and airbox to pry the batt. strap clip back and lift the snorkel out....

get a copy of dirt rider mag june 05 it has a full article on all the free mods for the wr450 with pictures. :banghead:

I just sold my 2003 WR450F after 3 trouble-free years of riding. The bike comes stock jetted VERY lean. I rejetted to 48PJ and 158MJ, (you should go 162MJ, I ride often from sea-level to 4-5,000Ft) kept the stock needle and left the clip stock in the #4 slot. I bought a ZipTY fuel screw, but frankly, it was a waste of money. I never touched the fuel screw again, after I turned it out 2 turns. I rode the bike from below sea level (SoCal desert) to 11,500Ft in Utah and from San Diego, CA to Cabo San Lucas, Mexico on the same jetting and fuel screw setting--- it ran just fine and got a consistent 40+MPG. Remove the snorkle, cut holes in the right-side of the air box and install the GYT-R muffler insert. Go ride it.

One thing that I strongly recommend that you modify on your bike is the Starter Idler Gear. This gear was the cause of the infamous problem of the fly wheel coming loose on the 2003 WR450F. Update to the Idler Gear from the 2004 or later WR450F. Some folks have been lucky and never had a problem, but most people ended up spinning the fly wheels. The Loctite fix recommended from Yamaha DID NOT FIX the problem, it only created more problems. Instead of spinning the fly wheel, starters and cases began to break. The replacement parts are a little expensive $250-300--- work a deal with your Yamaha dealer, they know the bike had a design problem. The alternative is the STRONG possibility that you will have to push your bike back to the truck at the most inopportune time.

I have a GPR 2.0 Stabilizer (handle bar fits over the top of the stabilizer) and an Applied triple clamp for fat bars (had Renthals on the bike) from that 2003 WR450F that you should consider buying from me. GPR Stabilizers are great. Good company to work with and they provide free life time maintenance service on their product. Long deal $550--- let me know and we'll talk. :banghead:

BajaFool, how does the sound output with the insert compare to the stock 03 WR 450 pipe? Or another way to compare is how much quieter does it make the bike than going no baffle or insert?

First let me say, "I hate loud exhausts!!!" They cause motorcyclists no end of problems by annoying everyone who has to listen to them. The GYT-R Muffler Insert will allow your bike to meet the 96db sound test. I detected no reduction in performance over the stock muffler insert.

Sorry for my ignorance--but how does 96 db compare to the stock pipe? I'm guessing from your post that that is still fairly quiet?

The sound level requirement for riding on US Forest Service and Bureau of Land Management administered lands, as well as many state lands is 96db. The 2003 WR450F stock muffler is certified to meet this level in California, where the sound level is 96db. With the GYT-R Muffler Insert installed, the stock muffler is still as quiet or quieter than 96db.

Gotcha! And, with the after factory insert, there's a bit more power, I hope!

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