How do you remove stuck carb bolts?

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DreamV4

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I use drimel, cut them for flat screwdriver or 2 sides to grab with pliers.
 

Fire-medic

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Just did it the other day. Used a small hand held impact and hammer.
Yes. Careful use of an impact driver will 99% of the time prevent the need for Dremels and chisels and all that nonsense.
I suggest anyone take the less dangerous method of disassembly. If you use an impact tool, you stand a good chance of cracking a carburetor body. Since some of the bodies/complete carbs are no-longer available through Yamaha, this is not something to have-to face. Hammers and carburetors should be mutually-exclusive/separate. Never the twain shall meet.

I suggest any of three methods.

[1] Use the correct security screw tip for the job. Harbor Freight sells an inexpensive set which will allow you to use a 1/4" hex screwdriver holder to simply loosen the screw, or you can use a 1/4" ratchet and a 1/4" socket with the tip, if you want more leverage.

[2] Use a pair of 10" straight-jaw Vise-Grips. Placed correctly on the screw, and locked in-place, that pesky screw doesn't stand a chance. With a bit of care, all the CV cap screws are accessible.

[3] My trusty Dremel, a thick, fiber-reinforced cut-off blade, a steady hand, and cutting a slot in the screw head. Make the slot so one of your 'good' screwdrivers fits your slot, snugly, and across the width of the screw head. It takes longer to eat a candy bar than to grind several screws, and it's better for your teeth! You might ask yourself, "Is it safe?" Movie fans of 1970's thrillers should understand the reference.

The zinc alloy the carburetors are made-from is brittle, especially when you're using a 16 oz. ball pein hammer and an impact tool. Don't be 'that-guy.'
 

apsolus

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im pact driver works great, who asked this guy? lol ^
 

02GF74

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Impact driver and hammer making sure the carb is supported on a block of wood directly underneath.
 

MaxMidnight

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I use drimel, cut them for flat screwdriver or 2 sides to grab with pliers.

Start with the correct screwdriver you need a JIS form on the end. One on a T bar will give greater leverage

With the screwdriver inserted tap the end of it several times, push hard on the driver and apply a slow but steady torque. Apply an increasing amount of torque whist maintaining the pressure on the end of the driver.
If still stuck apply some dismantling fluid and leave overnight.

Try again.

If still no-go or you have intercoursed the end of the screw then resort to the more extreme methods mentioned above.
 

02GF74

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The trick is to prevent the screwdriver from slipping, which is why an impact driver is recommended else pressing /hitting the screwdriver also works.

A tip that I've come across but not tried is to put some valve grinding paste on the tip to improve grip.

My JIS screwdrivers have a slot in the handle so another screwdriver could be used as a lever, whilst another set have hex shafts so a spanner could be used to lever.

I've just noticed that JIS bits are available for an impact driver...... should I buy.....?

BTW to overhaul the carbs, you just need to split them into 2 pairs so don't need to remove the large set screws (which is what I did as one of them I could not remove)
 

dannymax

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Impacts are fine if used properly. As Mr Midnight mentioned several sharp taps on the offending fastener to begin with then use the impact...seat it properly preload it in the remove direction then a few more aggressive taps and it usually will start to move.
Never whack an unloaded impact hard enough to transmit the energy thru to the carb body....THAT is what breaks stuff.
And of course the proper screwdriver head is very important
 
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I’m 52 years old and have disassembled/rebuilt my 01 carbs 5 times now. Not sure how hard Fire-medic thinks you hit the impact but that’s the best way to get a screw out. There is way more risk of damaging a carburetor with a Dremel, vice grips or pliers. If you scratch or scuff the zinc coating the the part will start oxidizing.
I will say no matter how you get it out replace all the screws with stainless hex head bolts using anti-seize on every one of them. It’ll make your life way easier the next time.
Sean Morley (One2DMax) can supply a complete kit.
 

maleko89

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I've had a float bowl drain screw rounded out for 10+ years. It's recessed so if/when I decide to fix it, will need to use a drill bit and ez-out.
 

Stephan

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One of my greatest triumphs (no not a Speed Twin) was when I drilled out a Vmax pilot screw (I call it an air screw) successfully. One slip and I would have been looking at that parts diagram above. I have protected all four of my air screws now by tapping out the recess drilling (to M7 x 1.0mm I think it was) and making some short stainless steel screws to plug the holes.
 

apsolus

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One of my greatest triumphs (no not a Speed Twin) was when I drilled out a Vmax pilot screw (I call it an air screw) successfully. One slip and I would have been looking at that parts diagram above. I have protected all four of my air screws now by tapping out the recess drilling (to M7 x 1.0mm I think it was) and making some short stainless steel screws to plug the holes.
i had to deal with one that wouldnt turn during my first rebuild. i ended up taking that carb to a machinist for extraction
 
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