EC300 Idle Revisited.

[Skidad]

Yes the Kawasaki MX bikes have the notch in the slides. You can get them for about $55 online in a 7 or 8 size but I dont think that's the issue really. I do want one of those notched slides to do some comparison tuning.

You could have an air leak in the throtte body where the needle jet and idle circuit assy attaches with those tamper proof torx screws. The choke plunger could be leaking air. A guy on KTM Talk went so far as to completely block the choke hole in the bell housing and found the carb worked better but would still start.

I say you need to get someone elses 38mm carb and swap it into your bike with your jets and see what happens. This will quickly determine if the carb has a problem.