WR450 jetting Q's

OK I did it. I started a WR450 only jetting Q's post. Now lets get things rolling with TT members that have actually rejetted their bikes. Lets build a knowledge base for the WR450. First thing I have noticed is the bike needs a leaner starter jet in the summer a 62 is working well for me right now to get quick e-starts. Try pulling in your hot start while having a richer starter jet and you will see what I am saying.

OK, here you go.

I have rejetted to:

YZ 450 needle (NCVQ) 4th position.

162 main.

42 pilot.

Turned acc. pump adjuster 1\2 turn clockwise.

This is with all the free mods and uncorked pipe.

I am riding anywhere from 1000 to 6000 feet elevation. My bike has excellant throttle response with no hesitation anywhere. No popping or backfires on decel. I can tell it is a little rich in higher elevations but not to the point of sputtering or anything. You can just feel it loses a little and can even hear a differant tone in the exhaust.

I have been running the stock #70 PAJ. today I ran it with a #100 PAJ to be the same as the YZ. I thought that might cure the rich condition at higher altitudes. It did. But it was too lean on the pilot circuit. It developed some popping on decel and lost some of the hit off the bottom. It was unseasonably cold today though. That may have contributed to it being too lean. I will try the same combo when it is hot again to see if it gets better. I may also try the #100 PAJ with a #45 or #48 pilot. That may be just the right combo. All in all I am happy with the above jetting and the #70 PAJ though.

I am running the stock #65 starter jet and have had no problems with starting. Usually it lights up on the first rotation of the starter.

Hope this helps, :)


Lowedog, what is the fuel screw setting?--

Here is a list of information to post:


Pilot Jet- #45

Pilot Air Jet- #70

Fuel Screw- 1 1/2 turns out

Needle- OBDUT

Clip Position- #4 (counted from the top)

Main Jet- #150

Main Air Jet(None=#200)

(Correct me if wrong, this can be edited... thanks LTR)


Fuel screw changes with altitude and also as the day heats up. But for a base line it is 1.5 turns out for most of my riding wich is 1000-3000 feet elevation. This is with the #70 PAJ. With the #100 PAJ it was out 2-1\4 turns and this was above 4000 feet.

Also the Stock PJ is a #45 for the WR.


JD- The stock pj is a 45 and the main is 150. Mine came with a 145 and 155 main, and a 140 pj in a little bag.

I am finding the same pilot circuit needs as Lowedog. I am best at a 100paj/48pj or a 70paj/45pj. I think the WR450s need more pilot then the WR400/426 carbs. I am glad someonelse if finding this instead of accepting poor performance. I hope James Dean makes needle kits for us like he does for the KTMs. We could use his help in that arena. Has anyone tried James Dean KTM 450 needles on a WR450? I would like to know. I may just have to order them and give it a try. :)

Give you 3 guesses why I'm here... :)

Yes, there is a jet kit in the works. A WR400/426/450 jet kit with altitude and temperature recommendations. There is also a YZ450F in my garage being tested with one of the custom triple taper needles.

The needles are a blend of WR and YZ needles made to smooth the transition from idle and give better over-rev capability. Expect more torque right from idle, improved mid-range equal to a YZF, and more on top by conforming an uncorked WR to YZ spec. The kit has been dyno tested on the KTM, altitude tested (to 12,500ft), and confirmed results by hundreds of KTM riders.

Look for it in the "Shop TT Now" cart in the next few weeks, after I iron out the details on clip position and main jets.



JD, since we are fellow Washingtonians you should send me over a kit to "test" out for ya on the WR. :) I could give you the feed back for the more arrid eastern side of the state. :D

Seriuosly though that is great news. I can't wait to give it a try!



You can sign me up for the jet kit as soon as it's out. I ride a lot of slow tight stuff here in GA and have had no luck with off idle bog. :)

160 main, 48 pilot, zip-ty fuel screw (irrelavent, just makes fuel screw adjustments easier), GYT-R insert, Euro needle (obduq), I too adjust fuel screw with temp changes. I live at about 500ft. I have no bogging, stalling, hard starting issues. Bike seems pretty sensitive to fuel screw settings (like the pilot screw on my two strokes). The Zip-ty fuel screw makes it easier to adjust it on the trail. I understand there are more folks making something similar. I used a small screwdriver that is about 1 inch long that I got at Harbour Frieght for .49 before I got the Zip-Ty. It's got a pretty thick handle (about 3/4") so it's easy to use with gloves on. It worked pretty good, you can't beat the price either. :)

Way to go James Dean! Count me in. I will order the kit as soon as it is ready. Thanks for supporting the Yamaha fourstrokes and us TT members. I am sure you will get a good number of orders. I think I recently read good reviews on your KTM needles in Dirt Bike. Congratulations on getting the recognition you deserve.

Hey Motocrash,

Where did you get that Euro needle? I can't order one through my dealer. They said I should contact a European dealer to order the OBDUQ part.

Greg :)

Just to keep this post fresh here is my latest settings.

NCVQ needle position #4

162 main

45 pilot

100 pilot air jet

1-3\4 turns out on FS

See my prior posts for results on PJ-PAJ changes. I went to a 45 pilot today to try it with the 100 PAJ. I think this combo is the best yet. Throttle response is the best it has been. It may be just a little rich in the transition into midrange but it's so close it's hard to tell. I'm not sure what to try next. Either lower the needle one position or go to a 40 PJ with a 70 PAJ. I think I will ride it where it's at for this weekend though.



I'm at 4500 feet, and these are the best settings I have found so far:

NCVQ needle clip 3

155 main (I haven't tried any others yet)

42 pilot jet

100 pilot air jet

me + jetting = :)

Hey guys we need more members posting a yes to custom needles for the WR Yamaha's. I think we want James Dean to get motivated into making the WR needles for all of us! Please post your thoughts for James Dean to see. :)

Put me down for the James Dean Kit (if he desides to make it). Sounds like a real winner!!!! :):D

Yes the James Dean kit sounds like a winner before its produced. You can add me to the list also.

well here are my specs I think i got one of the first JD Kits :)


james dean red needle 4th clip position

170 main

1.5 turns out

Baja baffle in

air box opened

I put the JD kit in and gain a big inprovement down low of stock.The thing screams from cruising to the rev limiter real quick.I'm real happy with the jd kit and hope to get some more power once i get a decent pipe on the bike. :D

I'd be interested in one too! Have not changed too much at this time but is much better than stock. Looking foward to perfection! :D

Smoke :)

well here are my specs I think i got one of the first JD Kits :D

You did get one of the first WR400/426/450 kits. James is in the process of putting the final touches on the kits and getting them packaged. We will be adding them to the TT Store soon so keep checking under the new products! :)

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