I'm stuck...really stuck.

[great white]

Another possibility is to buy a replacement mixture screw, look at how deep you need to go to just clear the threads, set up a depth stop and drill right down the center of the stub. Then expand out in drill sizes until you can pick whats left of the screw threads out. The rest should come out easy and you save to orifice in the body.

Drilling right down the center will be the biggest pita. I woukd recommend doing it on a mill so you can fixture the mixture screw absolutely vertical and the mill/quill will also be more precise.

If you do elect to drill it out, know going in that you might very well have to order a new carb body. One slip and……

 

[lordbeezer]

On my super B carb air mixture screw is in almost same place. Mine is straight down where yours is angled for easier adjustment. Still movable after being on shelf 10 years. Should’ve removed same for picture. Contraption on side is a accelerator pump I made. Worked pretty good.

 

[lordbeezer]

So when took picture. In front of air screw in picture is fuel enrichment valve.

 

[Flynth]

If you do elect to make a slot, don’t use a NA common screwdriver. They have tapered sides that will try and “cam” itself out of the slot. Get yourself a JIS common screwdriver. JIS has straight sides that help “bite” into the slot.If you have an impact driver, those bits will have striaght sides like a JIS driver.

I second the above. Don't use a normal flat head screwdriver. Best is if you have gunsmithing flat screwdrivers with hollow grind. If not you can easily make one with a piece of silver steel drill rod. I managed to disassemble a 160 year old Belgian black powder muzzle loader with multiple stuck screws (in wood and steel including one really seized up nipple) by making hollow grind tools for screws. Make sure to harden it and draw to straw yellow. It's best I found to grind half way before hardening and the other half after. I also ground flats on the silver steel rod so I could grab it with an ordinary wrench to turn and I used a block of wood to press it into the slot. The most difficult screw I worked out like this was 10mm diameter(a bit under half inch) with a 0.4mm (18 thou) slot.

Also, heat cycling and ultrasonic cleaner are your friends. When heat cycling get it at least sufficiently hot to make a sizzling sound when touched by something wet.

Slow and steady is best. Once you've cut a slot and you have your screwdriver in, turn it with feel. Try to guess the strength of the slot and try to stay 20% below it's breaking point. Go forward and back if its still stuck after heat cycling.

Worst case scenario the slot breaks repeatedly. In such case if this is brass in aluminium housing I would consider micro tig brazing, or drilling it out with a left hand drill bit smaller than the thread. Perhaps it backs off half way through drilling?

My worst experiences like this is with my Aprilia 125rs two stroke. Last time I was swapping the starter motor I broke half of a steel screw 5mm(a quarter inch) deep in an aluminium thread. After lots of unsuccessful attempts of trying to hit it with a punch I took out my mig welder (no way to get in there with tig as it was under the bike too) and I just welded little squirts of metal on top until it was above the surface, then I welded a nut on top. Then I tried to turn it and the nut and the weld broke off... Repeat 5 times and it did back out.. Thread saved.

 

[Bone Head]

1st. That's the idle mixture screw according to S&S. Meters fuel into the venturi.
2nd. S&S will sell me a new body for an "E". So if I blow this one up I'm not dead.
Screw's about a #10-32. Grinding/cutting a slot isn't something I want to tackle with a dremel. The hint about filing the body down to get a bettr bite on it appeals to me (thank you Great White).

 

[tq60]

Is there enough to solder to?

You may be able to get something like a sleeve to fit over it.

A BLUE butt splice may be close.

The heat from soldering may help.

The sleeve can be squished on opposite side for screwdriver or you can add something like a rod bent like a "T" to grab.

A good 250 watt Weller should get enough heat to do the job.

Then do th wiggle turn to get it to come loose.

Sent from my SM-G781V using Tapatalk

 

[Bone Head]

Is there enough to solder to?

You may be able to get something like a sleeve to fit over it.

A BLUE butt splice may be close.

The heat from soldering may help.

The sleeve can be squished on opposite side for screwdriver or you can add something like a rod bent like a "T" to grab.

A good 250 watt Weller should get enough heat to do the job.

Then do th wiggle turn to get it to come loose.

Sent from my SM-G781V using Tapatalk

Thanks, may use that one, The mess is going to remain soaking for a bit longer.

 

[great white]

Brass and aluminum have pretty similar expansion rates. If heat doesn’t work, buy a can of “spray freeze” and shoot that down the hole the idle screw is in. If you’re lucky, it may shrink the brass enough to allow it to break loose. I wouldn’t hold out a lot of hope for it to work, but when you get down to the last few tricks, sometimes desperate works…

 

[lordbeezer]

If all else fails drill everything out. Make insert to press in..Thread for new adjustment screw.

 

[lordbeezer]

Or shell drill bit(small hole saw). Cut just enough to get a grip on screw. Not gonna take a lot of thread to hold screw.