Help with jetting part numbers

3 replies to this topic
  • 4mud

Posted May 25, 2005 - 06:23 AM


I have a Canadian 2004 WR450 and I am getting ready to do the free mods. It is my understanding that the Canadian version does not have the grey wire or the airbox baffle. I have a PMB exhaust insert to install and will do the cutouts on the side of the airbox.

I ride at 0 to 1000ft of elevation. And have read the jetting database and other threads. For jetting I would like to use:
168 main, needle OBDUQ-4 (stock), 48 pilot (stock), 1.5 turns, 70 starter jet, #40 leak jet

I am a bit confused about the starter jet versus pilot air jet. Should I leave my pilot air jet at the stock #80 and change the starter jet from the stock#65 to a #70?

The local Yamaha dealer could only confidently say that he could get me the 168 main. He was confused between the starter jet and the pilot air jet. And he could find no reference to the leak jet at all.

Can anyone out there give me some help with part numbers?

Sorry about yet another jetting question, but I do need some help. This is only my second jetting experience. Thanks. :)

  • 4mud

Posted May 26, 2005 - 10:54 AM


Found part numbers in the Jetting Database.

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  • clark4131

Posted May 26, 2005 - 05:07 PM


I have a full FMF system and I opened up my airbox with a Barnum's Pro Airbox kit. Since the bike was breathing so much air, I put in a #100 Pilot Air Jet. I honestly couldn't tell that it made much difference, but I figured since that's what is stock on a YZ, and since it has a more free flowing intake, I figured it couldn't hurt. As far as the starter jet goes, unless you're having difficulty starting, you don't need to touch it. Now how your dealer got the two confused is beyond me as PAJ is in the intake bell of the carb and the SJ is in the fuel bowl. Are you sure he wasn't talking about the Pilot Jet rather than the PAJ? If so, then that is also in the fuel bowl right next to the Main. Here are some part numbers...

4MX-14943-88-00 .JET, MAIN (#152) AP 1
4MX-14943-38-00 .JET, MAIN (#155) AP 1
4MX-14943-89-00 .JET, MAIN (#158) AP 1
4MX-14943-39-00 .JET, MAIN (#160) AP 1
4MX-14943-90-00 .JET, MAIN (#162) AP 1
4MX-14943-40-00 .JET, MAIN (#165) STD 1
4MX-14943-91-00 .JET, MAIN (#168) AP 1
4MX-14943-41-00 .JET, MAIN (#170) AP 1
4MX-14943-92-00 .JET, MAIN (#172) AP 1
4MX-14943-42-00 .JET, MAIN (#175) AP 1
4MX-14943-93-00 .JET, MAIN (#178) AP 1

4MX-14948-01-00 .JET, SLOW (#35) AP 1
4MX-14948-02-00 .JET, SLOW (#38) AP 1
4MX-14948-03-00 .JET, SLOW (#40) AP 1
4MX-14948-04-00 .JET, SLOW (#42) AP 1
4MX-14948-05-00 .JET, SLOW (#45) STD 1
4MX-14948-06-00 .JET, SLOW (#48) AP 1
4MX-14948-07-00 .JET, SLOW (#50) AP 1

3TJ-1494F-12-00 .JET (#62) AP 1
3TJ-1494F-13-00 .JET (#65) STD 1
3TJ-1494F-14-00 .JET (#68) AP 1
3TJ-1494F-15-00 .JET (#70) AP 1
3TJ-1494F-16-00 .JET (#72) AP 1
3TJ-1494F-17-00 .JET (#75) AP 1
3TJ-1494F-18-00 .JET (#78) AP 1
3TJ-1494F-19-00 .JET (#80) AP 1
3TJ-1494F-20-00 .JET (#82) AP 1

4JT-1494F-01-00 .JET (#35) AP 1
4JT-1494F-03-00 .JET (#40) AP 1
4JT-1494F-07-00 .JET (#50) STD 1
4JT-1494F-11-00 .JET (#60) AP 1
4JT-1494F-15-00 .JET (#70) AP 1
4JT-1494F-19-00 .JET (#80) AP 1
4JT-1494F-23-00 .JET (#90) AP 1
4JT-1494F-27-00 .JET (#100) AP 1


  • UltraHyper

Posted May 30, 2005 - 03:03 AM


Thank Steve appreciate it,this forum is a god sent,I think that exactly what he was doing


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