bike running rich

[riffraff]

Well if it's a Mikuni I know the have a great manual available that explains everything with step by step procedures, I've got it saved on my computer along with the 2 stroke tuners handbook.

[kawi250]

it is a 05 kx250, the carb is a keihin pwk38s

[ford832]

Report?

[kawi250]

Ok I just finished initially the screw was like two and a half turns out. I just bought it and the guy said he kept it rich to be safe so I unscrewed it two full turns out and it ripped I swear I had better throttle response and harder power bans. I was worried it sounded like it was idleig too high though so I turned it to the right two quarter turns or a half and it sounds as I think it should and idles all day long. So now I am roughly one and a half turns out and I think I'm good to go! Was I right in richening it since I thought it was idleing to high?

[kawi250]

My last post was a little rushed and im still confused at how the air screw was so far out to begin with? turning it to the right richened it and i started by turning it all the way to the right. then backed it out 2 turns which is when i noticed a power difference(or think i did anyways) the bike was ideling better but after i got back and listened to it idle without a helmet on i was concerned it was ideling to high, which is when i richened it or turned the screw to the right a half turn. now it seems to be idleing as it should and isn't dying like it was before. My question is should i go by sound? or performance? i have yet to ride it after the half turn in since i had something to do but plan on test riding the new position tomorrow but thought it was safe to assume that since the bike is idleing good it should ride good as well

[ford832]

Firstly,the last guy  had it leaned out if he was 2 1/2 turns out.By turning it 2 out you richened it a bit.If your idle dropped when you turned it in to 1 1/2 you've gone too far.For your airscrew setting,you want the highest idle-2 turns by the sound of it.Once there,turn your "idle screw"(above the Keihin marking-likely black plastic head with a spring behind it directly to the rear of the bike from your choke knob)to the left(counterclockwise) until the idle drops to where you want it.The airscrew shouldn't be used to set your idle as this gives you the wrong setting.
If two turns out turns out to be your best setting you're in range but almost at the lean extent.If the temperature where you ride goes up  much more in the summer you can go out to about 2 1/2 then but after that you will need to switch to one size smaller(leaner)pilot jet.
As for sound/feel/performance setting,I set it first by rpm/sound then ride it.After that,try turning it in 1/8 turn or so to see if it's a bit better-if not,go out the same and try it again.If both are worse,return to your original setting.Sometimes the best performance will be slightly to one side or the other of the max rpm setting.Of course,once the temp changes you'll have to readjust to maintain it.Colder temps-richer/hotter temps-leaner.
That's why it's good to have the bike jetted for your usual riding temps.That way,slight temp changes can be taken care of quickly with just an airscrew adjustment.Eg.,if say your usual riding temp is 70'F and you have a pilot jet in it that allows you have your screw at 1 1/2 turns out you can typically go about 1 turn out for 60' or 2 turns out for 80'.More or less anyway.

[kawi250]

haha ok this is going to show how new to this i am. the only screw i adjusted was the screw with the black plastic head and that was the screw that 2 and a half turns out. i did the steps i listed before to the idle screw (with the black plastic head) and now that screw is set at just about 1 and a half turns out. I guess i was not specific enough in my original post. the bike was never bogging just idling to low, and the plugs were getting really black and almost had liquid exhaust on them. so maybe my problem was just the idle screw? i hope this helps better clarify what i adjusted

[kawi250]

and for future reference can you give me any helpful hints to identify my air screw? please excuse the fact that i am such a noob haha

[TMKIWI]

The idle mixture screw is below the "N" in Keihin.

[ford832]

What tmkiwi said.It's a little brass screw that sits flush with the carb.Try it agian with that one.

[kawi250]

Ok I'll give that a shot. And I shouldn't be worried about the idle screw I adjusted last time right? Since I Haha it idleing where I want it I can re adjust it after I lean the bike out.

[ford832]

Turn the idle down as low as you can,then set your airscrew.Once done,put your idle where you want it.

[kawi250]

Ok two last questions before I go try it. If the bike was running good and just idling rich and low isn't it a possibility that only the idle screw needed to be adjusted? And second turning the idle low is richening the idle and turning that screw to the right correct?

[G-MONEY]

 Hey kawi250 just try this,warm the bike up hold the throttle to a fast idle 1000 r.p.ms then adjust the brass screw in and out till it sounds the best to you then set the plastic one to your likeing. You can do this as much as you want.From cool morning rides to hot afternoon rides to dial in your bike. If you have burbbling (rich) or surging (lean) in your throttle range let us know let us know then we can zero in on pilot jets,mains or needles.

[kawi250]

when setting the idle how will I know what's low or high? do i turn it down meaning really rich and high meaning really lean and tell by sound? im gonna give it a go tomorrow to get ready for southwick this sunday!