help no manual/jetting

5 replies to this topic
  • gary.m

Posted May 11, 2002 - 11:40 PM


i need some infomation on the 00 wr stock jetting i have just bought the bike and have no manual it has a staintune muffler air box cover removned it has flat spot at 1/8 throttle. 0000-2000 feet apart from that bike goes great

  • skippy

Posted May 12, 2002 - 12:19 AM


Great to see another aussie use this site. Nobody I know in Newcastle use's this site.
I'm no jetting expert but I reckon your pilot jet is too big.
I'm useing a 35 pilot & a 55 paj. It is now very crisp off the bottom.

  • SealClubber

Posted May 12, 2002 - 07:36 AM


I would order a manual from the dealer. I think Baja Designs sells them too. Also I saw a Clymer Manual for the bike and they are about $25 US.

What does a flat spot usually indicate, lean or rich?


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  • Mark_Cantrell

Posted May 12, 2002 - 09:25 PM


A flat spot can be lean, rich, or the CDI (grey wire). If you haven't removed the grey wire, do that before trying to jet it away.

The beauty of a flat spot that low is that you can use the fuel screw to experiment with. It is a flat blade screw deeply recessed in the bottom front of the carb, essentially straight up from the bottom in front of the bowl. In for less gas, out for more gas. When you find which way helps, search for more on the fuel screw for whether or not you need a different pilot.

At 1/8th throttle, the needle is just coming into play. There are suggestions (mainly the xxDMM needle) for replacement needles. If you take your jets out and see what they really are (instead of what the last owner said they are), I'll plug your jetting and jetting with a DMM into JD's spreadsheet and let you know what the DMM would do to the 1/8 throttle position.

Good luck,

p.s., its at a basic level so don't read it if you're past that, but the 'Jetting 101' post on the YZ/WR250F forum may help get started with the carb.

pps., The manual for these bikes is awesome. Get the real manual instead of Clymer. Money very well spent.

  • James_Dean

Posted May 12, 2002 - 10:48 AM


Now to answer the question about what jetting is stock... :)


#42 pilot jet
#75 pilot air jet
1 1/2 turns out on fuel screw
OBDRQ needle
clip position #4 (4th from top= middle)
#165 main jet
#200 main air jet

#65 starter jet (choke jet)

Try turning out the fuel screw to 2-3 turns to help the 1/8 throttle.

A bigger pilot jet(#45) or smaller pilot air jet(#60?) will help get the fuel screw closer to 1 1/2 turns.


  • gary.m

Posted May 14, 2002 - 11:33 PM


thanks for the info ive turned the pilot air screw out 1 3/4 and it has made a fair bit of difference no more back fire or poping the flat spot is still there but only just cant realy tell in the bush but still anoying anyway will try turning out a bit more if not go up on the pilot ...can any one tell me if the usa bikes are the same as australias in spec...thanks gazza


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