richer or leaner?

Fellow TT'ers,

My plug is black on the outside of the electrode, and the electrode is still grey. The bike runs very very well, and starts on the first or second kick cold with the choke and will usually start with no hot or choke after a fall. I intend to turn the PAS out a bit with the intended result of richening up the pilot circuit over all.

I had dropped the clip to position three on the stock needle but got some louder backfires when backing off from high speed runs, so I moved it back to position two. That tells me that I should be perfect on the WOT side.

Somebody check my logic here. I think I am on the right track but......just checking.

Thanks in advance for your help.


Im about 100 feet below sea level where i ride in the pits of southern cali. The stock jetting works wonders down here. When i went up to sanbernandino bout 2000 feet that is the first time i heard it backfire while riding the the fire roads.. I did however turn the PAS out bout 1/2 turn and that made a slight improvement... Now it runs great anywhere i take it.. no hesitation.

My Plug readings were exactly like yours. When I changed the SJ from 65 to 55 the Carbon ring on the bottom of the plug disappeared. Now the plug is clean with a grey electrode.

Bonzai :)

must be nice. I have 12 different people telling me wat to do. I think i will just sat screw it and keep changing out plugs. How damn frustrating


are you turning a PAS or the pilot screw under the carb?


i believe that when the jetting is right that you will still get a soft backfire. so forget it. there's an argument that in order to stop the backfie the bikes are jetted rich just to stop them.

i can suggest that in order to lean the slow speed you should get a smaller (38PJ) instead of turning out the PAS.


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