1980 Special - Sticky Carbs?

The way I did mine was after I stripped the heads even with the right screwdriver and a good backing, I used an extra thin drill bit and went straight down using the remnant of the phillips slotting to locate the bit. The drill turned the screws right out the back side like nothing. It didn't touch the shaft threads. I'd almost recommend that as the normal way to get them out. The screw metal is very soft
 
Update: I managed to drill them out on a spare (junk) carb without any drama. Taped off the holes, packed the carb with a paper towel, sprayed it down with a 1:1 mix of acetone and ATF… The heads came out, I got the shanks very carefully with a long pair of needle nose pliers, I’ll tell you what drill bit I used in a minute. The threads on the shaft don’t appear to be buggered at all! I checked the seals, they’re definitely old and worn, but… It seems weird that these would be my problem. Any air leak after the carbs is bad, sure, but like… What do you guys torque your carb boots to? They’re old, they’re hard, they’re a bear to get on… Should I get new ones?
If hard and cracked I’d get new ones.
 
If you mean torque for the clamp screws on the manifold, I don't think there ever was one given, you just make them good and tight. I tighten the screws fully, until the two clamp halves touch. You may not be able to do this if you still have the original Phillips screws on there and their heads have been buggered up a bit. I switch to Allens. The originals are a rather long 20 to 25mm, longer than need be. An M5 x 16 fits and works just fine .....

ManifoldClamp2.jpg


Also of note in the pic above is the nice, thick original style manifold gasket. Besides sealing, I think this serves another purpose, isolating the manifold and carb from engine heat. Many of the replacement manifolds come with plain thin paper gaskets. I won't use those. Original style thick ones are readily available from several suppliers (YamahaXS650.com, MikesXS). And let me mention the manifold clamps again. The aftermarket replacements for them are something else I won't use because they come with smaller M4 screws. I don't think they clamp as well.
 
Yeah, I just kinda very carefully gave it the business.
Haha I know what you mean. Here's what I would follow if I did it again. Carefully Dremel most of the staking off the back. Put a piece of wood through the carb for backing, in a bench vise if you have one. Little bit of heat from a minitorch, let cool, little bit of spray. Try to twist it out with a JIS bit. It probably wouldn't hurt to tap the bit lightly with a hammer to help seat it. If it didn't work, get a drill bit the same size as the head and drill down to destroy most of the head but don't hit the shaft with it. Use what's left of the phillips slot to center a drill bit, maybe half the diameter of the screw, keep 'er straight and slow and there she goes out the back. While you still have the head, might be fun to try a 1/4" impact driver. Well backed up! I didn't try that.
 
Yes, I lightly tap the insert bit a couple times with a small hammer (4 oz. ball peen) to seat it in the screw head firmly, then I use a T handle holder on the bit. These are the best. You can exert tremendous downward pressure and turning force with one of these. The ones I need to drill out are far and few between. They've come out fine with the T handle on the last 5 sets I've refurbed.
 
I've just done it that once. The bane of my existence is I do lots better the second time around but usually only need to do a thing once. PLAN AHEad as the poster says, to limit the destruction.
 
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