some may not,
I thought I would share, and hope others will participate with positive input, and logical suggestions or questions.
OK, so I have a few carbs laying around the garage....
Left to right>>
97 CR250 keihin PJ38 with powerjet
99 CR250 PWK 38 airstriker
01 KX250 PWK 38 airstriker powerjet with TPS
Left
I have never ran or used the 97 cr250 carb.
It has the largest fuel inlet, a large float bowl capacity, powejet located at 50% tp.
Center:
99 CR250 carb... I ran one of these bored out to ~ 40.5 mm and then offset 3mm up, with the top of the slide milled to clear the opening.
It was essentially ~ 40.5 x 43mm, and a nightmare to jet. We did not cut out the air stryker vanes or mod the bell/ volute on the airfilter side.
I think an intellijet would have helped immensly.
Immediatly I noticed the kx250 carb looked to have more material, in hopes it would be bored out bigger, but the inner bell taper is whats different. The outer volute dimensions are the same as the others. The idle air screw cct, and choke ccts are position the same as the other pwk carbs, limiting the size it can be bored.
I like the powerjet option, but even more so the TPS.
powejet is located at the 1/4 throttle position
needle jet has casting modifiactions in front of needle, for better atomization and higher velocity at the needle, acting like an aerofoil I imagine.
Like I said in the past, my last bike had an issue with timing. I think the right curve would have helped immensly, but a 3d ignition curve could possibly be great addition.
The biggest break though in 4 stroke carburetion was the FCR carb, mostly because of the accelerator pump.... it dumps extra fuel richening the cct, when they wack it open.... another issue I found with my last built cr500 motor. Powerjet could be useful. I couldn't seem to tune out a lean spot when I opened the throttle fast, it would ping 2-3 times at a specific rpm, when wfo,
Maybe just an intellijet would have fixed that ?
The fourstrokes also got better with 3D ignition timing, and TPS.
I would imagine detonation control, fuel loading, and improved fuel ccts would help the 2 strokes as well, especially the big bore though.
I may be on the wrong track, or I may not.
The things I don't like about the kxcarb... well it has the smallest fuel inlet port, smaller float bowl, least taper in the volute.
Most of that can be fixed if necessary.
opinions, and experience encouraged.
. put differences aside and be buds like me and bob. tell em bob, we tight aint we 
but i heard its good
