Pilot jet too lean?

6 replies to this topic
  • finglan

Posted October 28, 2002 - 12:39 PM


I am still trying to get my bike jetted. Right now I have a 38 pj, 160 mj, EKP#4.

At idle when I blip the throttle it idles higher and takes a long time to come back down to a normal idle.

I tried turning the pilot screw in and out. It made it worse in both directions. It was best at about 1.5 turns out but was still bad.

Do I need to go up or down on the pj?

Right now I have a 100 maj as I have tried another members jetting which ended up too rich. That was: 170 mj, 42 pj, 100 maj, EKP#4.

  • okieguy

Posted October 28, 2002 - 12:56 PM



The 38 pj seems too lean with the stock 75 paj unless you are at a higher altitude.

You might try to put the 42 pj back in and lower the needle a clip or two. You will be suprised how much the needle effects the whole jetting.

I have had best results with 35pj, 50 pas, emm-3, 155mj & 160 maj. also yz timmed.

Hope this helps

  • Wyatt

Posted October 28, 2002 - 02:43 PM


Try a 40 pilot before you settle back to the 42.

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  • LarryCO

Posted October 30, 2002 - 11:49 AM


I believe you meant to say you have a 100 PAJ...not a MAJ in there. The stock PAJ is a 75...while the stock MAJ is a 200.

There's certain combo's of PJ/PAJ's to use. If you truly have a 100PAJ...that's a very big jet...and one that should be used with a 45PJ or so.

Folks have been using the following combo's:
42PJ -> 75PAJ
40PJ -> 65-70PAJ
38PJ -> 60-65PAJ
35PJ -> 50-55PAJ.

Stick with the 35 or 38PJ...and get the corresponding PAJ's...or even easier, get the Sudco pilot air screw (PAS)...which can be used to attain all PAJ values based on how far out you unscrew it.

Good luck!

  • ricky1

Posted October 31, 2002 - 05:53 AM


I hope you are still out there.

Do you find that the relative settings for the PJ/PAJ hold true at any altitude? I live at 6500 ft and ride to 9000 several times a week. I have different valve springs, retainers, porting, (port cleanup?), and Hotcams, and I am trying to re-jet, with a little difficulty.


  • LarryCO

Posted October 31, 2002 - 11:18 AM


They're close suggestions...atleast to get you in the ballpark. You have to also consider the diameter of the jet needle you're using as well to finish off your pilot circuit (e.g. ekP, ekQ, etc).

Check out my "sig" below to find what I use at that same altitude. Works VERY WELL for me in CO at Rampart Range...

Good luck!

  • ricky1

Posted October 31, 2002 - 11:50 AM


Thanks Larry,

Your settings are nearly the same as I used to run. That will get me back in the ballpark.


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