Stuck pilot air screws

Hi all, after some more tips here. Going throught the carbs on my 1981 KZ750 H2, it seems the #2,3 and 4 pilot air screws are seized solid in their ports. I have an exact fit screwdriver but you can feel the head of the screw start to flex under pressure. I have soaked in plus gas for 2 days, no movement, tried heat and freeze spray...nothing.
I then filed down to just above the screw just clear of the head as we do not have blanking plugs in the UK, just to see whats happening. It looks like the slot has opened up a bit, possibly causing the outer spline to lock on the port?
Going inside the engine side of the carb I can blow through the air pilot port with carb cleaner and it flows fine.
Checking with a cranked over needle, I can feel the ends of the pilot air screws and they all appear to be about the same.The one that does move is about 1 3/4 turns out.
Is there a way to get these out as replacements are unavailable or should I try changing pilot jets to a larger size to improve idle.
Currently running Pods, 4 into 1 Scorpion, primary main #70 secondary main #140.
Waiting for the vacuum gauges to come for setting up sync.
Cheers
Pete

Soak the screws in Kroil for a couple days. Ed

Soaking with PB Blaster, Kroil, or another will help. But I've had to drill down and use a small easy out. Then heat the outer carb body at the screw, expanding the casting. A hot small butane torch will heat the body quickly, without heating the screw as much. I spent 4 days on one screw for a friend before. Soaking and heating, it came out without damage to the carb. Be careful and patient.
New screws can be ordered, or some rebuild kits will have them.

PB Blaster and Kroil are good stuff.
soak and give it a tap now and then to set up vibration (patients)is the key learn to walk away some times and have a shot of Old Crow.

i just did some carbs that the float pins where tight and i mean tight but they came out with soaking in PB Blaster but when i installed them dress the ends of pins alitte with file and arkansas stone.

PB and an impact driver has worked for me on many a stuck screw. If i cant replace it i either source a junk yard or chace all my threads. When dealing with carbs or any place metal is bad i use a magnet followed by compressed air and an extremely thorough cleaning to ensure all metal shavings are removed after my thread repair.

silentchris wrote: PB and an impact driver has worked for me on many a stuck screw. If i cant replace it i either source a junk yard or chace all my threads. When dealing with carbs or any place metal is bad i use a magnet followed by compressed air and an extremely thorough cleaning to ensure all metal shavings are removed after my thread repair.

The air screws are brass, dont use an impact driver unless you want your flat head groove totally gone. Brass isnt magnetic either. :whistle:
I heat them, but keep in mind, you can put too much heat to it, because the brass will swell as much as the aluminum and wont move anyway.
If the groove is messed up where the flat blade goes, file the top flat on the screw and use a hacksaw blade to regroove the top of the screw. Then keep light pressure turning with screw driver, only apply heat to the carb around outside of screw not the screw itself. As it warms and are still applying turning pressure it should start to move. If it gets too hot, cool it all and repeat process.
Only very rarely could I not get one to eventually move.

I always use a trim hammer and am extremely gentle. Just want to loosen the corrosion in the threads and the magnet is for the metal on the carb side. I've never tried this on bike carbs but I have done a few old webbers and an individual stromberg setup this way. It does work if one is for gentle.

Cheers oldschoolz.
Will keep trying, been a week now with still no movement. Tried freeze spray on screw, heating outside still nothing. Kroil hard to get in the uk but I think we have pb blaster. Even tried heating with oil in the screw to draw it in...still nothing yet. Spent so much time on these carbs can't give up now.
Pete

What Chris said, is true for metal (I believe he was simply unaware that the screws are brass)
If you have to end up drilling the center of the screw, make a small hole in the screw and find a hardened Torx bit thats slightly larger than the hole(should be able to lightly tap in the torx bit, then heat and apply turning pressure.
Spiral extractors will spread the screw and lock it tight(They are good for stripping the hole out)
A torx bit only grabs the screw where the points stick out and dont spread near as bad.
I've removed some tough extractions with them.

If all else fails, as a member said above, you can use a drill bit slightly larger than the small shaft of the air screw and drill the top part until the bottom of the needle is no longer connected and then remove it all piece by piece. They can be mean to you sometimes. :laugh:

If you can not get Kroil try mixing 1:1 some automatic trans fluid and kerosene and use it to soak the screws for a day or so. They will loosen up.

That sounds good, just not sure if i can get spare ones here in the uk, will keep searching. if they come out i can recut the slot no problem.Otherwise it is a case of destroy and replace if possible.
soaking again now in tectane po496.

Cheers

Cheers Motörhead.
Still trying, any idea where I can order replacement screws, not found any in uk yet?
Cheers
Pete