air screw adustment question
- Thread starter turbotim
- Start date
If you turn your a/f mixture screw clockwise all the way till it stop and then you back it out 1.5 turns- 2 turns, thats all you should mess with. If your jetting is too rich or lean by alot, Just rejet your carb. So to answer your question, to richen you tighten (right), to lean out you losen (left). Hope this helps!
I thought on my kx 125 was clockwise to lean it, So witch way is it? I got a blaster they said needed a top end rebuild well i took off oil inj. and had some 40-1 laying around and i know i need 32-1 i just have no money! So it quited it down a lot and the idle was really high (fixed also!) Now its starting to run good so im fine tuning and need to no witch way leans and witch way richens for a better peace of mind! Im at one turn out, from all the way in right now!
Now, let's go look at the bottom end of the carb tuning.
In general, a TWO stroke carb has an Air Screw adjustment - which will be on the AIR FILTER SIDE of the carb's slide.
Most of the time, the air screw is set about 1-1/2 turns out from fully seated - this is a good base line starting point.
At first, adjust the Air Screw in 1/2 turn increments so you can see the difference. Then start being more finite by making 1/4 turn adjustments. You'll eventually get to where you only need to make adjustments in 1/8 turn increments.
Get your ride idling in neutral (warm it up fully first)
Quickly nail the throttle, going from idle to wide open in a smooth manner, but quick manner.
Just stabbing the throttle as fast as you can may cause enough disruption in the flow of the intake that the engine can't keep up - eventually, when the carb's tuned correctly, you should be able to nail it and have the engine react correctly. You'll see how this works as you tune the carb.
What does the engine do?
Does it hesitate and then rev up?
As it comes back down to idle, does it seem to hang at a higher idle for a minute and then settle down to normal idle?
If it does this you're Too Lean on the Air Screw adjusment. You need to richen it up by turning the Air Screw IN 1/2 turn and then repeat the test.
Adjust as necessary, repeating the test until you have a nice response.
Or
Does it sound like it bogs a bit?
As it comes back down to idle, does it seem to drop to a low idle (or even die) and then come back to normal?
If it does this, it's Too Rich. Turn the Air Screw out 1/2 turn.
Adjust as necessary, repeating the test until you have a nice response.
Remember: Adjust the Air Screw in 1/2 turn increments at first then fine tune with 1/4 turn and then 1/8 turn increments.
Repeat the proper adjustment until it responds without hesitation and drops back to idle without hanging or falling and then coming back up. Expect to do the bottom end adjustment at least three or four times before you get it right.
Go write down your findings
Now that you have a base line setting, try adjusting the air screw a full turn either way and see how the engine reacts. You'll soon see what the air screw does. Since you WROTE DOWN what you found, you'll be able to go right back to that adjustment point.
Found that on a website. Hope fully it answers your question. I made the bold lettering for the importance.
Just the opposite.
Over 2 turns out, go down a pilot size.
I went from a 50 to a 42 on my carb. What a difference.
Most of the time, the air screw is set about 1-1/2 turns out from fully seated - this is a good base line starting point.
At first, adjust the Air Screw in 1/2 turn increments so you can see the difference. Then start being more finite by making 1/4 turn adjustments. You'll eventually get to where you only need to make adjustments in 1/8 turn increments.
Get your ride idling in neutral (warm it up fully first)
Quickly nail the throttle, going from idle to wide open in a smooth manner, but quick manner.
Just stabbing the throttle as fast as you can may cause enough disruption in the flow of the intake that the engine can't keep up - eventually, when the carb's tuned correctly, you should be able to nail it and have the engine react correctly. You'll see how this works as you tune the carb.
What does the engine do?
Does it hesitate and then rev up?
As it comes back down to idle, does it seem to hang at a higher idle for a minute and then settle down to normal idle?
If it does this you're Too Lean on the Air Screw adjusment. You need to richen it up by turning the Air Screw IN 1/2 turn and then repeat the test.
Adjust as necessary, repeating the test until you have a nice response.
At first, adjust the Air Screw in 1/2 turn increments so you can see the difference. Then start being more finite by making 1/4 turn adjustments. You'll eventually get to where you only need to make adjustments in 1/8 turn increments.
Get your ride idling in neutral (warm it up fully first)
Quickly nail the throttle, going from idle to wide open in a smooth manner, but quick manner.
Just stabbing the throttle as fast as you can may cause enough disruption in the flow of the intake that the engine can't keep up - eventually, when the carb's tuned correctly, you should be able to nail it and have the engine react correctly. You'll see how this works as you tune the carb.
What does the engine do?
Does it hesitate and then rev up?
As it comes back down to idle, does it seem to hang at a higher idle for a minute and then settle down to normal idle?
If it does this you're Too Lean on the Air Screw adjusment. You need to richen it up by turning the Air Screw IN 1/2 turn and then repeat the test.
Adjust as necessary, repeating the test until you have a nice response.
hi i have a blaster with a strait air filter and boysen dual stage reeds and also an fmf full pipe. how many turns should i adjust my airscrew to and how does the turns go is a turn like a 360 degree turn or what. please help i really dont know much about the airs screw
Well turn the air screw all the way in till it stops -no further!
then one full (360°) turn and one half (180°) turn start there! Should be close but depends on what carb, what pilot (slow jet) you have! That's considered 1.5 turns out!
With a stock 32.5 pilot, a correctly adjusted float, and a clean needle and seat so the carb is not flooding, adjust as below.
Idle adjusting.
Start with air screw 1.5 turns out.
Set idle screw so that it has some sort of idle. With TORS big screw under seat on top of unit. No TORS brass screw midway down carb body.
Warm up motor and then set idle screw for a faster idle, 2000rpm+
Adjust air screw either way to get the fastest idle.
Adjust air screw a little at a time leaving 10 secs to allow the motor to respond.
Re adjust idle screw for desired idle .
Idle adjusting.
Start with air screw 1.5 turns out.
Set idle screw so that it has some sort of idle. With TORS big screw under seat on top of unit. No TORS brass screw midway down carb body.
Warm up motor and then set idle screw for a faster idle, 2000rpm+
Adjust air screw either way to get the fastest idle.
Adjust air screw a little at a time leaving 10 secs to allow the motor to respond.
Re adjust idle screw for desired idle .
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