125-200cc PWK 38mm Idle screw (not air screw) adjust??

[dunc]

Help!
Idle seems to vary day to day, air screw is good at about 1 3/4 turns out, but confusing myself
with the idle screw. If I screw it in the idle goes up and if I screw it out the idle goes up??
I start at about 3 turns out and which way am I supposed to go??

Carb from JD, installed 2 months ago. 185main, blue needle in 3 or 4 (stock settings) runs good,
at holding half throttle it goes brp, brp, brp which means its rich on the needle? also going to drop to the 180 or 170 main now it is warming up. Second half to WOT it sings nice.

 

[Dirtdame]

At some point, if you turned the idle screw out far enough, the bike wouldn't idle any more because your slide would be completely shut....unless....you didn't have enough freeplay in your throttle cable. You should have at least 3 millimeters of play at the throttle. With the engine off, you should be able to hear the slide hit the adjuster screw when you pull the throttle open and then let it close again. First make sure that you have the proper freeplay in your cable before diagnosing anything.

 

[marcmo0]

If second half to wot is good your main is most likely ok, or close to it. Half throttle is your needle, but without knowing more info hard to tell. What elevation and temps? Did you check the jetting thread? Lots of good info. Fwiw on my 09 300 with same carb i have a 40 pilot, jd red needle on 2nd clip, 160 main. Elevation i ride now is from 5,000-9,000 with temps in the 60's and 70's.

 

[BCdirtbikegal]

I have the same carb on my WR150, and it's set about the same as yours for jetting but clip position 2 on the blue needle. Idle is easy to adjust, same as Dirtdame said if you turn it far enough out the bike just shuts off. You want it high enough so it isn't stalling out on you. Not sure why it would vary so much day to day though. http://www.cafehusky.com/threads/keihin-pwk-carb-decoder.23334/#post-208503 is a good post about tuning the carb.

 

[dunc]

I'm at about 700 ASL, and temps are 60-70 right now. I will check the throttle free play there was not much room when I put it together.
The bike is a 133 with a Fast by Ferraci head, so I guess it probably has been ported as well, so not sure what the racier head might act like when it is not going full blast. Looked at the jetting database and I seem a little rich so I'll check the free play, 185 on the main sounds high (have 180 and 170 in a bag), and check the needle to possibly drop it down one clip. Starts great 2-3 easy kicks. If I stop and close the throttle it might stall, but if I give it a little throttle for a few seconds then it will idle. Thanks for the suggestions.

 

[ohmygewd]

Main jet does nothing for your idle and if you are screwing out your idle screw only results in increasing the idle, check that the cable free length adjuster is not screwing itself out when you are revving.
If the adjuster is firm, warm the bike up and screw in the air screw, catch the motor before it dies, then screw it out until the idle is smoother then screw it out further. At this point, the idle should be at the highest rpm as screwing out further makes nil effect ...how turns out is the air screw? If its past 3 turns out then you need a smaller pilot jet and if only a turn out then a larger pilot.
Now you can adjust the idle screw with far greater accuracy once you determine whether your pilot jet size is correct.

If everything, carbwise, is sound then you have a probable air leak.

The symptoms in your last post suggests that your pilot, possible slide size, and needle clip height or float level is not right as pulling up to a stop a near stalling indicates a too rich setting around 0-1/2 throttle.... Warm the bike up, ride at 1/4 throttle and then go WOT, if it bogs then your focus area is the pilot and clip height....forget the main unless you ride 3/4 to WOT majority of the time..