09 WR450 Jetting Question

I just got a new 09 WR450 and next week will be doing all the free mods, leaving the AIS on for now, and rejetting. Live in Colorado, around 5k feet.

My question is I want to do this a cheap as possible. Can I get good performace just by following the recomendations on the jetting data base with individual stock jets and using a 04' WR needle, or is it really worth the money to get the JD kit with their needles?

Also I am alittle confused about using a stock needle. I have read some places that I should use the stock 04' WR needle and other places to use a YZ needle. Which is the one I need YZ or WR needle?


I think the main thing is that if you use the JD kit, you will be at a point where most people here can offer advise regarding tuning as I think the majority of the people here have gone with this kit. You can probably do nearly as well with stock Yamaha needs and such, but the other jetting specs won't line up with those that have the JD kit as their needles have different tapers and so require different jets than someone that uses a Yamaha part.

Look around at the database and try and find someone at the same elevation as you for starters and see what worked for them. This is a bike that is not much fun to re-jet so hopefully you can get it right the first time. I followed JD's specs and it still did not work out perfectly for my location, so I had to go back in a redo the pilot and go with the leakjet that most people here seemed to find success with.

I have a 2008 WR-450 and live at about 800" in Atlanta Georgia. My bike ran like crap when I picked it up. (Backfired, spitted and sputtered) It now runs awesome. Here is what I did.

1. Removed the Airbox Snorkel (easy and free)

2. Cut the Grey wire under the left number plate (Easy and free)

3. Cut the Throttle stop screw. (free but make sure you cut it to the right length. Better to be slightly longer than too short)

4. Replaced the Pilot jet with a 48. (You may not need to do this in Colorado)

5. Installed a 2004 WR-450 adjustable Needle Jet ($18) The WR needle is Leaner than the YZ and may be better at altitude

6. Made my own AIS removal kit. (bought rubber vaccum caps from Auotzone, made my own aluminum block-off plate. $3)

7. Installed an adjustable Fuel screw. ($20)

Search the WR forum and you'll find all the details you need to do these Mods correctly...

I'm around 3 '08 WR's in Denver, and all run great with 48 pilots at 1 3/4 turns out, stock needle and clip, and a 155 main. Whether at Rampart range at 8,000 feet, or at Moab, where we put in a 158 main, they run cleanly.

Thanks for the replies,

I decided to just get the JD kit, sounds like people have had good luck with it and if I have problems witht the jetting there will be alot more people running the same set up that I can compare too. And if I only have to take the carb out once that will be a plus too:thumbsup:

Hopfully the weather will be good over christmas so I can get some time in riding. Sucks having a brand new bike sitting in the gargae for weeks with out riding it :moon:

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