Snapped pilot screw on 250sx carb... now what?

[wonderboy]

I wanted to make a small adjustment to the pilot screw on my 85 SX. First I tried a flat screwdriver, but the slot split open (that should have been my first clue that this was not going to end well). So I sprayed the screw down with PB blaster and grabbed it with the vice grips... yup, the end just snapped clean off, flush with the carb body.

I wasn't done yet, so I grabbed the dremel with a cutoff wheel and put a new slot in the end of the screw. I put a nice clean groove in the end of the broken part. Tried with the biggest screwdriver that would fit cleanly and nothing. Even tried a little bit of heat (didn't want to damage anything else while I was in there) but nothing.

So my question is: has anyone successfully drilled out the pilot screw without destroying the carb body and the orifice at the bottom?

I'm good at drilling out broken bolts when the surrounding material isn't so important, then heli-coiling and moving on with life. I'm wondering if in this case, I should just look for a used carb on e-bay just to get a usable carb body, then transfer my existing carb guts over. Or do you think I'll be able to get this stupid pilot screw out?

[hoosierlogger]

Sounds like you should look for another carb to me.

[hillbilly 200x]

try a hammer and punch hit it once or twice, the shock will usually break the seal and let you turn it out

[wonderboy]

I'll give the punch trick a try. Also, I'm gonna spray on the PB blaster and let it sit overnight. Thanks for the tip!

[dougspcs]

I say time to give it up McGyver..you're boned! Mine did the same thing, but I was lucky..a little WD and gentle vise-grip use got it to loosen. Dissimilar metals and 25 year machines don't mix well.

There is a guy in the trading board that has a 250es for parts. Might just as well check with him.

[jb2wheels]

Try a reverse pitch drill bit. They spin the "wrong" way so when they bite into the screw they try to spin it out instead of in.

[Ironbnder]

I have rebuildable Big Red carbs shipped for $45.

[oscarmayer]

you can look at upgrading to a 350x carb now! ;)

[wonderboy]

Thanks for all the info guys. I'll probably go for a good rebuildable carb. Once I have something on the machine, I'll continue my efforts to remove that stupid screw (it's a matter of pride now).

I was thinking of the "upgrade" option as well. Since I own a 350x, I thought about getting the 400EX carb on the 350X, then passing the 350X carb on down to the SX. But, I'm really not a good carb tuner (yes, it begs the question "what was I doing messing with the pilot screw in the first place"). If the 400EX didn't just work out of the box, I'm afraid that I wouldn't be able to get it working well. Oh well, something to think about...

[Dirtcrasher]

Tap on it and they snap the whole casting off, there's a spring in there that goes "GA-BOING!!"

From that gentle tap till now, I've milled them out, has to be dead nuts and there isn't enough room for a helicoil.........

[rdlsz24]

I did the same on a Big Red 250 carb. I tried my best to get it out but I ended up buying a different carb

Rob

[bradshea]

you should be able to get a small enough easy out.

[wonderboy]

I'm the heli-coil king... I love those things. It sucks that there isn't room for one in there. I hate easy outs. Must be my technique or something. For frozen bolts, I don't think that I've ever successfully removed one with an easy out... thus my love for heli-coils. I just drill out, tap, and insert the coil, which in my opinion is a way better thread than what was originally there since now I'd have a steel bolt in steel threads. (ok, not in the case of the carb, it'd be brass on steel... )

Hey dirtcrasher, with the mill setup, how do you finish the process? Specifically, when you've cut down through the screw deep into the bore, you're left with a bit of brass still engaged in the threads and the tip of the screw in the bottom of the hole. What do you do to get this out? I'm no good with a mill, but the guys at work may be able to bail me out if I can explain exactly what I want to do.

[oscarmayer]

happy times.. *ding* :lol:

[muthey]

You have to chase the threads with a correct metric tap, is how they put them in there in the first place. Good luck with your endeavor.

[Dirtcrasher]

Unless you put a similar screw in their hand, they'll be lost. If it's drilled correctly all thats left is the needle which falls/taps out.

[ailll1]

Happend the exact same thing to me. Flat screw driver broke one of the side of the screw, so I thought: why not use a vice grip to remove it? Snapped right off! :mad:
Tried e-z out, broke inside the screw. Ended up trying to spin it with a small punch but, of course, the part that sticks out of the carb wasn't strong enough and broke.

Had to buy a use one on ebay for about 50bucks plus a rebuilt kit. Runs like a top now.

P.S: At least I had a reason to mess with the pilot screw, it was running like crap.