Help Needed Jetting on '03 WR450...


5 replies to this topic
  • wpoling

Posted May 24, 2005 - 01:29 AM

#1

I need some help on a '03 WR450. I've done a good bit of searching over the site, but still have some questions. First off, it's not my bike. A good friend or mine is deployed in Iraq and I'm trying to help out his son. I've done a good bit of jetting on two strokes, but the newer 4 strokes are new to me.

He busted his head pipe and replaced it with an FMF Powerbomb SX, the stock silencer has been uncorked, stock air filter, airbox baffle has been removed, and he's racing at elevations of 800' - 2000'. The jetting was stock until I installed a 165 main jet which helped a bunch.

My questions are: Can you just buy a single JD needle? Looking at the database I probably need a Blue or Red one. What all comes in the JD kit? He really doesn't have $65 to spend. I'm not familair with the starter jets or leak jets, where can I find a diaghram showing their location in the carb? What are the stock sizes on the leak jet and the starter jets? Where can I buy them? Local dealer had never heard of them. Where can I find a list and "how to " do all the free mods? Found a great site for the WR250 but not much on the 450.

Thanks to all for the info you have already provided and any advice you can provide.
Bill

  • clark4131

Posted May 24, 2005 - 05:55 AM

#2

ThumperFAQ also applies to the 450, though it is geared towards the 250. A 165 sounds a bit lean for that elevation, especially since you've opened up the pipe and airbox. What size is your pilot jet?

If it starts fine, leave the starter jet alone.

The leak jet is in the bottom of the float bowl and can be had from Sudco...they call it the Accelerator Pump jet. Diagrams can be had on the Yamaha parts site.

The JD kit comes complete with two needles, main jets and instructions. The needles are not sold separately.

There you have it...SC

  • ncmountainman

Posted May 24, 2005 - 06:15 AM

#3

try the 04 wr needle(DWR) it was much improved over 03 and is only $12. part # is 5TJ-14916-WR-00 :)

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  • wpoling

Posted May 24, 2005 - 12:59 PM

#4

ThumperFAQ also applies to the 450, though it is geared towards the 250. A 165 sounds a bit lean for that elevation, especially since you've opened up the pipe and airbox. What size is your pilot jet?


The pilot jet is a 45 (stock). I'm trying to come up with a 48 pilot and a 168 main locally. The shops around here just don't carry many jets. Will probably have to order.

Thanks,
Bill

  • Indy_WR450

Posted May 24, 2005 - 03:52 PM

#5

The 03 likes the 165/160 mains with JD red needles in the east during the summer. Run the JD red #5, 48 pilot with 1.75 turns out, 165 main and #40 leak jet. When it gets real hot go to a 160 main, JD red #4 , 45 pilot 2 turns out and a #50 leak jet. :)

  • wpoling

Posted May 25, 2005 - 01:15 AM

#6

Thanks to all for the suggestions. I'm assuming the number with the needle refers to the clip position? Now does anybody have a Red JD needle they would be interested in selling?

If not, I'll look for the needle the Mountainman refered to from a '04 WR.

Thanks again,
Bill




 
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