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1997 KTM 250 EXC Jetting

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Hello all,

I have a 1997 KTM 250 EXC that I believe needs jetted. Below is the info for my riding and the bike. 

Carb: Keihin PWK 38

Main Jet: 175

Pilot Jet: 45

Needle and Position: Unsure of how to check that.

Air Screw: 1.5

Altitude: 700-2000ft above sea level

Temperature: 60-90 degrees fahrenheit

Style: Tight Single Track, All throttle ranges, but do lug quite a bit as I ride with slower riders

Plug: BR8EIX (Just Replaced)

Fresh Air Filter

The bike has a ton of splooge coming from the exhaust, as well as having trouble idling both with and without load. It has also been fouling plugs. 

I did some research and found a chart for a 1999 250 EXC and it says to do a 178 Main, 45 Pilot, N"some symbol"C in position 2 with the Air screw 1.25 turns out. 

This is a dumb question, but does the air screw refer to the black plastic capped screw with the spring, or the brass screw lower and to the right?


Thank you in advance to anybody who helps!


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FWIW I run a 40 pilot and 170 main. Air screw (brass screw is air screw, the other is idle speed) needle at 2nd clip from the top. Spooge is less but I'm going to go down to a165 main and run the needle at the 3rd or 4th clip position because although I haven't fouls my plug it was freakin black :facepalm:

i run super M at 50:1 92 pump gas and ride fast tight trail. 

Edited by Builderdude

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