KDXRIDER.NET

The bike: 98 kdx200
The owner(me): 15 year experienced auto mechanic and power equipment including 2 strokes

Here's a quick history on the bike. 2 owners. Both older guys. Never beat on or raced. I bought it from the second owner who had it sitting for many years. Barely ridden. On to the present day. I pulled it out of my shed yesterday. Drained all old fuel and added fresh 32:1 mix with Spectro synthetic. Brand new NGK spark plug. Opened up the fuel valve,pulled up the choke and kicked it over and she fired up and ran. After a minute or two I pushed the choke lever down and she idled really high. Pulled the choke back up and it ran beautiful. I went around the yard a few times then shut it off. Now, besides the fact that I should clean the carb(which I plan on) I checked the air screw. It's only set at 1/2 of a turn out from fully closed. I thought that was odd.

I am friends with the previous owners Son and he stated it always needed to be run on choke ever since his father owned it. Now that sorta leads me to believe it's not specifically just a dirty carb issue but something else. My questions are....Any other ideas besides the possibility of an air leak from intake gaskets,crank seals? Also WHAT Are the Base Carb settings? Air screw,needle clip,float height. So when I remove the carb I can compare those settings to what it currently is. Maybe something is incorrect.

Sounds like an air leak. The high idle sounds like a lean condition. The choke is actually an "enricher", it adds fuel. If the bike runs "properly" with the choke on, it's getting air from somewhere else, I'd assume after the carb.
First order of business is to remove the carb and check the air boot. Then the seal around the reeds. Clean the carb and replace the seals and boot (if needed). Look for oil inside the stator cover as well.

That kinda what I expected. I will definitely be checking all that out. Was there also a stick post on here for factory service manual?

You also will need to check the jetting make sure someone hasn't put to lean a pilot jet in Average pilot should be in the 40--45 range. If they put a way to small pilot jet in you would need the choke to run. Clean the carb too.

I'm pulling the carb after work today. Which I suspected it of being dirty. I misunderstood the owners Son. Communication error. What he meant was "the last time he had it running it would only run on choke" Although there may still be bigger problems I suspect the carb being the issue at the moment. Regarding the air screw, is 1/2 turn out the correct setting or does that seem to have been fiddled with? I can't locate that information. Base needle clip setting? I see float height is 16mm

Factory setting
Air screw 1 1/2 + or - 1/4
Main jet #160
Pilot jet #48
Needle clip 3rd from the top
Float height 16mm + or - 2mm