2003 WR450 Q's


11 replies to this topic
  • Toothmech

Posted September 25, 2006 - 06:22 PM

#1

Hey there- new to the forum, and I am probably going to take some flak for this post, but I have searched everywhere and I can't find decent jetting tables for a 2003 WR450. The searches here have led me all over the place with lots of great info on the 05 and 06's, the Off-Road.com website's links are busted to the section on modifications for the 2003 project bike, so no dice there either. The bike is jetted stock according to the previous owner (bought it two days ago, my first 4-stroke offroader), but has the wire grey wire disconnected, the insert taken out of the silencer, an adjustable air screw, I will be chopping the airbox soon (is this the same as the 05 routine outlined here?), but it desperately needs to be jetted better (doesn't have the head-snapping acceleration I hoped for). The old bike is a 97 CR250, so I'd like the new one to have at least that amount of power. Any other recommendations would be appreciated too. Also noticed the suspension is a little mushy for my tastes. Where is the best place to send the suspension for a revalve for a 200lb rider in gear? Thanks for any input guys-

  • Indy_WR450

Posted September 25, 2006 - 06:35 PM

#2

Here is what works for me and you guys can use it as a starting point to jet your bikes derpending on mods:

[COLOR=Sienna]This recommendation requires air box flow mods and an open stock or aftermarket pipe and ACV circuit intact. [/COLOR]

Elevation 0 to 4,000. feet

30 to 45 degrees: 172 main, JD Blue #5, 48 Pilot, 2.0 turns, 75 starter jet, #0 leak jet
45 to 60 degrees: 170 main, JD Blue #4, 48 Pilot, 1.75 turns, 72 starter jet, #0 leak jet
60 to 75 degrees: 168 main, JD Blue #3 or JD Red #5, 48 Pilot, 1.5 turns, 70 starter jet, #40 leak jet
75 to 90 degrees: 165 main, JD Red #5, 48 Pilot, 1.25 turns, 68 starter jet, #50 leak jet
90 degrees plus: 160 main, JD Red #4, 45 Pilot, 2.0 turns, 65 starter jet, #60 leak jet

Elevation 4,000 to 8,000 feet:

30 to 45 degrees: 170 main, JD Blue #4, 48 Pilot, 1.75 turns, 72 starter jet, #0 leak jet
45 to 60 degrees: 168 main, JD Blue #3, 48 Pilot, 1.5 turns, 70 starter jet, #40 leak jet
60 to 75 degrees: 165 main, JD Red #5, 48 Pilot, 1.25 turns, 68 starter jet, #40 leak jet
75 to 90 degrees: 165 main, JD Red #5, 45 Pilot, 2.0 turns, 65 starter jet, #50 leak jet
90 degrees plus: 160 main, JD Red #4, 45 Pilot, 1.75 turns, 65 starter jet, #60 leak jet


Elevation 8,000 to 11,000 feet: ( Note you will loose a lot of power due to altitude but your bike will idle and not foul plugs!)
45 to 60 degrees: 165 main, JD Red #5, 48 Pilot, 1.25 turns, 70 starter jet, #40 leak jet
60 to 75 degrees: 160 main, JD Red #4 , 45 Pilot, 1.75 turns, 68 starter jet, #50 leak jet
75 to 90 degrees: 158 main, JD Red #3, 45 Pilot, 1.5 turns, 65 starter jet, #60 leak jet

  • ARin

Posted September 25, 2006 - 09:13 PM

#3

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  • bg10459

Posted September 26, 2006 - 05:34 AM

#4

FYI, I have an 03 WR450 with a YZ pipe and my jetting is very close to Indy's chart. I have not done any airbox mods (except removing the baffle), and I wouldn't recommend it if you do lots of off road riding with possible water crossings. The chart is a great baseline for you to do your own testing, but remember, you will need to be slightly leaner if you go with the stock pipe or if you don't do any airbox mods.

  • Toothmech

Posted September 26, 2006 - 08:38 AM

#5

What if you're sticking with the stock needle? I don't think the JD kit is worth the money. As far as I can tell the only thing you are paying for is the needles, other than that, 3-4 jets don't come to near $70. Anyways, if anyone would like to comment on their stock needle setting, it would be greatly appreciated. 4th clip is the stock setting, I imagine like everything else, I would have to raise it up to richen the mix. Does this fall in line with what you guys were thinking. What about a YZ needle from the same year? I'm going to buy the jets right now, and after that I'll start fiddling with everything else. Thanks again for all the help guys!

  • GCannon

Posted September 26, 2006 - 09:10 AM

#6

Don't forget the Throttle stop while you are in there.

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  • bg10459

Posted September 26, 2006 - 09:19 AM

#7

You can try an NCVQ needle, which is stock YZ. They're about $12. I couldn't tell you what clip position to use, but following the clip position from Indy's chart might not be a bad idea. Like I said, it's a good place to start your trial and error jetting.

Try doing a search for NCVQ

  • kskyles

Posted September 26, 2006 - 10:07 AM

#8

What if you're sticking with the stock needle? I don't think the JD kit is worth the money.


it seems a little expensive, but i think the JD kit was worth the $70. it saved me a ton of time, and those triple tapered needles are great. i've been telling my buddies that it is wise to spend more time and money on jetting then aftermarket exhaust, and other mods.

i've heard good things about the yz needles, but i've had personal success with the JD kit.

either way, you'll probably be cool. good luck, and make sure to post here when you've got it tuned and figured out.

  • RichBaker

Posted September 26, 2006 - 05:06 PM

#9

What if you're sticking with the stock needle? I don't think the JD kit is worth the money. As far as I can tell the only thing you are paying for is the needles, other than that, 3-4 jets don't come to near $70. Anyways, if anyone would like to comment on their stock needle setting, it would be greatly appreciated. 4th clip is the stock setting, I imagine like everything else, I would have to raise it up to richen the mix. Does this fall in line with what you guys were thinking. What about a YZ needle from the same year? I'm going to buy the jets right now, and after that I'll start fiddling with everything else. Thanks again for all the help guys!

I put an 04 WR needle in my 03 and love it...

  • Toothmech

Posted September 26, 2006 - 06:53 PM

#10

Alright- installed a 168 Main, 48 Pilot, (can't adjust the leak or starter jet yet), raised the needle 2 slots (6th one), screw 1.5turns out, and finished cutting the throttle stop to 19.2mm. The grey wire has been disconnected and the exhaust baffle removed. The "snorkel" has been removed according to the previous owner (although I can't verify that, because I don't know what it looks like), but no other airox mods yet. So what else does everybody recommend to achieve YZ type power? The only problem I am having is that when you rap the throttle open from any position, the engine stumbles or even dies occassionally. Is this related to one of the other two jets I haven't changed yet? Sorry, but i'm new to the high performance 4-stroke carbs :thumbsup: . Lots more tiny little parts than the 2-smokes i'm used to :lame: Anyways, thanks again for all the help so far!

  • bg10459

Posted September 26, 2006 - 07:46 PM

#11

The only problem I am having is that when you rap the throttle open from any position, the engine stumbles or even dies occassionally. Is this related to one of the other two jets I haven't changed yet?

Sure. Your leak jet affects the accelerator pump squirt.
I think it's the most important jet to have right on.

  • Toothmech

Posted September 27, 2006 - 07:10 AM

#12

Another question- getting ready to order the leak jets from the dealer and noticed on INDY450's jetting chart (it's great, thanks a ton!) that he specifies a #0 leak jet. When I looked up the parts on the Yamaha fiche though, it doesn't list a #0, the smallest is the #40. Does anyone know what's going on there? Is the #0 a typo or is there something else I am missing. If I redo the leak jet does it eliminate the need to reset the AP? The instructions to do that seem a little bit much. I don't even have a video camera to record the "squirt" so I really don't know how I am going to adjust it if I need to. It is set to factory specs as far as I know. In fact, I know that I am the first guy to open the carb. Anyways, appreciate all the help so far guys, this forum is a real lifesaver!




 
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