ACV Cover Allen Head Screws

I'm attempting to update the jetting in my carb similar to Taffy/LarryCo. I'm having a hell of a time getting one screw out of the ACV cover. I've completely twisted the Craftsman allen wrench and it still won't budge.

Any suggestions? I also had trouble with the one holding the slide inside the carb.

Why are these small diameter screws so tight? Is there Loctite on the threads?

Any help would be appreciated.

Mine had Loctite, and were a b**** also. I ended up using a pair of side cutters:

Come straight down, on top of the allen screw with the tip of the side cutters. Then just squeeze hard and turn hard.

Use the blue handle Lineman’s side cutters, they’re tuff as nails!

I'll have to go to the store and get some side cutters.

I went to Sears and got a new set of small vise grips and new allen wrenches. Got the screw holding the slide out and it had a ton of blue Loctite on it.

The ACV cover screw is so tight that it completely rounded inside the head of the screw. The other one just had a touch of Loctite on it and came out relatively easy. This one is welded in solid.

The thing that bums me out is that Yamaha seems to use very cheap screws in a lot of areas and Loctites them in. My Vmax had the same problem and I spend about $20 on stainless screws on the 4 carbs.

Thanks for the suggestion.


Try some heat and a tap on the screw. Don't use a torch, or take the carb off and clean first.

I'll try heating it as well with a pencil soldering iron directly on the head of the screw.

I did a search for side cutters and I'm not quite sure what they look like. I just want to make sure it's not a tool I already have.

There is also a shop in Denver called Denver Mill and Lathe that can literally eat this screw out of the hole without damaging the carb body but I have to drive an hour each way to have it done. They remove broken studs out of aluminum engine blocks regularly with this piece of equipment.

Thanks guys.

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