Guys help me out on two questions - jetting & fuel screw

7 replies to this topic
  • RC81

Posted October 07, 2005 - 02:07 PM


Bike is an 05 WR450 with all free mods done, 168 main, 48 pilot, Quickshot and DR. D pipe. Just installed adj. fuel screw and want to know how you set it correctly. I hear about holding the revs up and adjusting for the best sound and a couple other ways, how do you guys do it? My other question is I just received my JD kit and was wondering if I should use the setup they give or if you have found otherwise. I mostly ride at sea level and not during very hot times. I really only want to do this once as I dont have the time or inclination to be changing needles and jets all the time. I guess what I am asking is there a happy medium I can go with. Thanks.

  • Indy_WR450

Posted October 07, 2005 - 03:53 PM


No happy medium exists. Plan to rejet for summer, fall & spring and winter. 3 times a year is what most riders do. JD jetting instructions are slightly on the rich side but it is a safe starting point. Go to:

You can learn a lot from this well prepared jetting section. :banghead:

  • clark4131

Posted October 07, 2005 - 03:55 PM


Here's where I'd start, 168 Main, 48 Pilot, JD Red #5, 40 Leak Jet, 70 Starter...Set it and forget it. To adjust you fuel screw, get the bike good and warmed up. About 20 minutes of good, solid riding will get you where you need to be. You should have your idle set at 1900 +/-. Start turning your fuel screw closed until you hear a change in the idle. Back it out until the RPMs return to normal. You're done...SC

  • RC81

Posted October 12, 2005 - 12:55 PM


At this time of year should I go with the red #5 or blue #3 needle and why?

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  • WR450F_RDR

Posted October 12, 2005 - 05:48 PM


if your at sea level most definitely go with the blue needle and since you have after market exhaust I would set it up with 170 main, 48 pilot, and about 2 turns on the Zip-tye fuel screw (if you dont have one, get one they make jetting a whole lot easier). To adjust fuel screw just screw it all the way in lightly and turn out 2 turns to start, I personally dont mess with trying to adjust while running. Red needle is best for higher altitudes. I have ridden mine at sea level at the dunes and all I have to do is lean out a little on the fuel screw and go ride.

  • old man dan

Posted October 12, 2005 - 10:32 PM


I live and ride at sea level to 1500 ft and current temps are around 50 60 degrees. JD blue #3 170 main 48 pilot 2.25 turns out. Set it up this a month ago when temps were 70ish and I thought it was pretty good, it works even better now that temps have fallen. (it does still pop on decel but who cares)

  • toyota_mdt_tech

Posted October 13, 2005 - 06:39 PM


I ride at sea level and up to about 3500 feet, sometimes higher, but not often. I have the JD kit, it said to start ewith the blue at #3 and a 170 main. I have since went to the 168 and will probably end up with the 165. I kept the blue needle in at #3 and the fuel screw (Zip Ty) out to about .75 turns. Rest of my carb is stock, it has no hiccups, flat spots, backfires etc. Since the JD kit, economy has suffered, main reason for me going to a smaller main jet.

  • RC81

Posted October 13, 2005 - 11:43 PM


I went with the 168, 48 and blue #3. I will take it out this weekend and see how it runs. Thanks for the advice all.


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