Barely riding the KLX lately because I have been commuting by bicycle since Feb, about 2500 miles this year so far. I got way too much on my project list, which I ignore and ride my bike as much as I can.
Eventually I will get the carb switched to the next set-up and will report results here.

 

Good on you for the bike riding. I wish I could commute on a bicycle and live to tell about it. Small county roads with about 6" berms and a ditch. It's a shame there aren't more bike path projects included with road improvements. I did walk to work about a mile one way when I was working that far from home - sidewalks all the way.

 

Had only few rides with this carb setup. What I noticed so far - mileage is about the same, but sometimes there is shooting exhaust sound when rapidly closing throttle at medium and high rpms.
Could it be due to drilled slide port, too rich midrange as you said before? Considering to fix the port or maybe to change the main jet to one size smaller...
Otherwise it's Ok

 

It is impossible to know what to do with main jets until you repair your lift port.
While the normal reaction is to kill top end power by re-jetting smaller to get the midrange correct, this is wrong thinking and incorrect action.. You get the midrange correct with a proper lift port, proper slide spring, proper needle, and proper needle clip setting on a main jet that allows best top end performance..

Stick a 3/32 bit in the port and JB weld around it... Or JB weld the port shut and re-drill it with a 3/32 bit..


I assume "shooting exhaust" means decel popping. This is fueled with the pilot system and has nothing to do with the main jet. It occurs when the pilot system is too lean.
If this condition started after your CVK setup session - you have likely created a fault.

So, these are the possible issues and fixes:
A vacuum leak is now occurring.
Your pilot system has developed a clog from debris and needs to be cleaned thoroughly.
The fuel screw needs adjusting to more turns out.
The pilot jet needs to be replaced to a #38 or a #40.

 

Well you big chicken, you. Scared of a little 4500 pound car and a blue-haired old lady?

LOL!...yeah, it gets interesting sometimes even when you have wide roads and big shoulders. I gave up road riding a long time ago what with motorists paying such close attention to traffic...not! Mountainbiking is way safer...and frankly more fun. Heck, I even avoid as much pavement as possible with my KLX now...LOL!

Of course on the other hand, you do find quite a few "duded out" in their little Tour De France costumes pedaling out in the traffic lane like they had good sense...and making lots of new friends with many motorists as they do so...LOL!

 

There are a few that I see frequently, who brave the early commuter traffic. I just don't trust 'em. Then there are the dump trucks taking gravel to construction sites from the gravel pit... nah, I'll take the Ranger, a cup of coffee, and NPR.

 

NPR??? I knew you were a commie!...LOL!

 

I'm sorry, you must have me confused with someone else, I've never been in Helsinki much less ever palled around with Putin...



Sorry, it was just there jumping out at me...

 

I accidentally listed 3/16 as the bit size for restoring the slide lift port - edited now, as can be seen above - to the correct 3/32 bit size..

 

Tried to change main jet from chinese #162 to chinese #155 and shooting sound is gone.
I think that was not decel popping, because shooting appeared from middle to high rpms. Decel popping was already eliminated some time ago by changing pilot jet to Kawa #40 size (tried also #35 and #38 before)
I'm not sure should I really need to do lift port repair... will see.

So, the current setup is: BB351, CVK carb, lift port drilled to ~3mm, lidless, Kawa #40 pilot jet, Chinese #155 main jet, OEM N5AV needle, stock header, performance slip-on
Previous setup was: #132 chinese main jet, N1TC needle to 3rd notch.

Cant feel power difference between those two, but now engine works smoother.
Mileage observations are still in progress.

One more thing - could someone please post a picture with OEM N5AV and Dynojet needles side by side?