96 Ktm 250 sx

That black screw is the idle control. It should be near 1.5 turns out from all the way and adjust from there. It looks like a Keihn PWK, probably the best carb for 2 strokes. That main jet sounds good for sea level, where you are. I would still double check a generic jetting chart or even see what other 250 guys are running with that carb.

If the idle is high make sure the throttle cable is moving freely and allowing the slide on the carb to close all the way.

I would put a fresh spark plug gapped correctly, not sure what the ktm calls for here, and go from there.


Bike looks really clean. You will like the 250 power. Get some fork protectors asap.

I'm just across the river in Vancouver.

I meant to say the idle screw should be as close to 1.5 turns out from all the way in.

Yeah if it doesn't sound pingy or detonation isn't occurring dropping a main will generally net more power. Try to find the sweet spot.

I can't help on power valves. I never had to service mine on my old hondas. My CR500 motor doesn't have one.


LaDee flats near Estacada OR is my favorite. Its about 40 min from pdx. 15 miles of a nice gravel road with single track and 4x4 trails spurring off. You can get some high speed rips in and some nice woods riding.

Sand Lake was fun but a dirtbike is a handful in the sand. Well only when you want to go slow lol

Try that jet and check the plug. Should be a milk chocolate color. White is detonation and near catastrophic failure and black is pig rich.

I would stick with current jetting and get a plug reading on it off a brand new plug and go from there. The bike might feel rich but is burning plugs that nice chocolate color anyways.


Something to consider: If you are rich at sea level, it will be even richer up in elevation, think Ripplebrook/Ladee is about 1500-2500 ft. So consider that when testing also.

I Jet my bike for sea level and adjust the air screw up to 2k feet. If I was going any higher and I would need to swap jets. You can get quite a bit of tuning out of the air screw on a Keihn pwk though.

No you lean out the jetting the higher up you go.

The less air available means you have to lower the fuel level with smaller jets.

Down at sea level the air is more dense and needs more fuel to match it. Which is why you can adjust the air intake screw on the carb and adjust for some altitude, some being the key word. Every bike will be different, some will want new jets flat out with a 2k elevation change.

If that is indeed the PWK air stryker model, I would check but it does look like one, it is well known to have a decent range of adjustment though.

Edit: When I jet for sea level, they are the biggest jets I have and I can "open" the air screw, by screwing it out, to let more air into the carb and mixture when I go up in elevation to account for the less dense air. This is still on the sea level jets. This is where you need to get into plug reading though as it might feel fine with just the air screw changes but the only true test is the plug test.

Glad you got it dialed in!

Those your other bikes?