Pilot Air Screw

oldncnile

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Ordered new slides, needles, and needle jets for this '81 I bought.
Dismantling the carbs so I can clean them, and found someone had drilled out the brass plugs over the air screws. And of course they went a little too far and the drill bit spun the screw in so far, and wiped out the slot for the screwdriver.
Has anyone ever had any luck getting one out? Easy out or left-hand drill bit? I've tried heat and PB blaster, but there is just not enough there to get any kind of bite for a screwdriver.

Thanks for any ideas.
 
Ordered new slides, needles, and needle jets for this '81 I bought.
Dismantling the carbs so I can clean them, and found someone had drilled out the brass plugs over the air screws. And of course they went a little too far and the drill bit spun the screw in so far, and wiped out the slot for the screwdriver.
Has anyone ever had any luck getting one out? Easy out or left-hand drill bit? I've tried heat and PB blaster, but there is just not enough there to get any kind of bite for a screwdriver.

Thanks for any ideas.
The heads on those air screws are pretty beefy, plenty of material to get a small drill bit into for an easy out removal.

If you're overly concerned about trying to drill straight for that deep of a hole (the screw heads down in there a ways as you probably well know by now), take it to a machine shop where they can properly set it in a drill press to drill deep and straight.

The only other way I've seen it done is to hack away at the carb body, removing the hole above the screw head so you have direct access to the screw head, but that ends up looking like hell, thus ruining the carb body, looks wise.
 
I wouldn't recommend the ones from Mike's, they're knock-offs. You can still get originals from Yamaha and they don't cost that much. Even though they never listed them for the 650 carbs, i managed to track them down because they do list them for many other similar CV carbs they use on other models.

https://www.partzilla.com/product/yamaha/12R-14105-00-00
 
I wouldn't recommend the ones from Mike's, they're knock-offs. You can still get originals from Yamaha and they don't cost that much. Even though they never listed them for the 650 carbs, i managed to track them down because they do list them for many other similar CV carbs they use on other models.

https://www.partzilla.com/product/yamaha/12R-14105-00-00
Thanks for the link. I checked a Yamaha parts site yesterday and didn't see them listed, so I figured I was SOL. I didn't think to check Mikes till Vincentdfan said they had them.
I much prefer factory parts if I can get them.

Thanks again.
 
So, taking this further, what is the next step of you DO drill out the stuck pilot screw And end up damaging the threads in the hole?
 
So, taking this further, what is the next step of you DO drill out the stuck pilot screw And end up damaging the threads in the hole?
Well, Part of mine came out. The bottom taper is buried in the orifice in the throat.
I've walked away from it for a while.
I chuckle to myself because I bought the motorcycle from a friend who said it ran just fine for him.:)
The diaphragms in both carbs had holes in them and the end of the pilot air screw is sticking down in the throat a 16th of an inch.
 
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