KLX300 36mm Mikuni pilot jet too small?

Hi all,

I've got a jetting issue with my Stroker-ized Mikuni 36mm. When I got my carb several years ago it came jetted close to the standard setup everybody else seems to be using - 127.5 main jet, 15 pilot jet, clip on 2nd groove from top. After reading the forums I bumped the main jet to 130 and moved the clip down to the 3rd groove. After several rides I realized that my pilot air screw was out 3.5 turns for good idle so I replaced the pilot jet with a 17.5.

The bike sat for over year until I finally got around to a complete restoration this year - frame powercoat (no more purple, yay!), Kibblewhite valves installed by 4strokeworks, and mild porting. It runs great now except that my pilot screw is back to 3.5 turns out for good idle. I've ordered the 20 pilot jet but I don't see that anybody else has gone for anything past a 15.

Am I crazy for thinking I need a 20 pilot jet? Could the pilot air jet be the wrong size? Is my bike just a gas guzzling freak at idle? Any feedback is welcome (well, maybe not just ANY feedback :lol: ).

Also, I disassembled the carb during the restoration and the chamber for the slide had a black coating which was flaking off. I read somewhere that they used a non-stick coating on some carbs. Does this sound right? I removed any loose pieces but may end up completely disassembling the carb to polish the offending surface since the coating is disintegrating.

1997 KLX300, Stroker headpipe, Pro-Circuit 496 muffler, airbox lid removed, backfire screen removed, crankcase vent tube restricter removed, sweet Kawasaki green powercoat.


You may have something partially blocking the pilot circuit. As you may know, the hole in the pilot jet is very small.

Ride on


Thanks brewster,

I'll make sure to check for any restrictions when I overhaul the carb. I forgot to add that I'm riding mostly SoCal deserts near sea level.

Is anybody using a 17.5 pilot or bigger?

Somehow I managed to order 4 pilot jets so if anybody has a need for a 20.0, PM me and I'll mail you one.

I'm still not sure about the black coating on the slide. Anybody else have any experiences?


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