With more testing and longer rides it became apparent that the 148 main was still way rich. I've worked my way down to a 138, I'll run that for a while and see how it goes. Went back up to a 40 on the pilot as well.

This thing runs a lot better than it did stock. I cannot understand the purpose of building a 351cc two stroke and putting a carb on it that would be suitable for nothing more than 175cc's.

After even more testing, I've found the N1AL needle to be excessively rich in the 1/2 throttle range. I've got a N2EJ in there now and I tried an NECJ which worked similarly well. The NECJ is a Suzuki needle which is currently available. I think I like the N2EJ a little better but I have no idea where it came from before it went into my box of jets. You might have a hard time finding one of those.

I've been all the way down to a 132 on the main and I'm back up to a 145. Might go back to the 148 too since the needle change has improved the mid throttle rich condition. I may richen the main until the mid throttle fueling goes chunky again and back it off just enough to clean it up.

You must be pretty close my dt250 is on a 144 main and a 35 pilot and the needle was an n2ej I think but its too rich and needs to be in the top slot to ride nicely I don't run a dt style filter and box though

I'm on the top notch as well. It works though. At lower altitudes it may work with a different setting, I ride around 5800 feet.

This thing is running a Uni pod filter. The stock airbox appeared to be passing dirt around the base plate of the air filter where it meets up to the outer casing. Fortunately this thing is almost entirely street ridden so it didn't have much opportunity to eat dirt. I've read the same thing in an old cycle world test so I guess these DT360's are prone to that.

Yeah mine is just as it comes off the pilot it's a touch blubbery but clears the moment you crack it open the slide cutaway is a bit small doesn't help cause its off a 125 I have a chinese slide on the way to butcher to the right cutaway and then going to do this mod I've been holding off until I get a slide cause it says it may make the needle richer and I don't have the leaner needles. Each needle letter is half a clip leaner I need to go 5 needles leaner
ktmtalk.com/showthread.php?539335-FREE-M...e-for-better-running

I've got a #5 slide in there now. I would like to try even less cutaway. I'm mostly concerned with running lean during high RPM cruising. That seems to be where this motor is most prone to detonating.

What throttle cable did you end up using to get the PWK 35mm to work with the oil injection? I assume you had to have something special made to work with the 1 into 2 splitter?

My one I just used the original cable and joiner even though I don't have an oil pump anymore I just run 20:1 premix. it's still in the middle of the cable I did have to make the joiner a bit longer to allow full throttle

Similar situation with my DT175: no joy with the carb I had. Threw on a 28mm flat-slide and I think it took me 2 goes to get the pilot jet right and maybe 3 for the main jet. Only sticking point was lack of an oil injection port. Thankfully there was an appropriate blanked off spot so I drilled it out and added a brass nipple.

I don't think anything dramatic happened performance-wise but certainly easier to work with.

I'm using the original DT360 throttle cable. It's a little long at the carb end so you need to make something to take up the slack. I used some parts I had laying around.