mixture screw busted-how to get it out please?

[marcovandevelde]

Hi guys, Unfortunately I have destroyed the groove in one of the air mixture screws of my 34 cv's off my 1100 kat . I need to adjust it as it idles far too rich now with pods and stage 3. I've separated it from the other carbs, and removed as much parts as I could. Can I heat it, or does anyone have another suggestion? PLEASE advise .

[KEITH KRAUSE]

There's been a lot of methods tried on this site. Heat guns, E-Z outs...
Cutting a new groove into the screw is the latest method, but that member also cut into the carb body with his dremel. Some members with a lot of patience and luck, have completely drilled out the screw. Risky.
Since you have the carb off and easy access...if you have a small enough drill bit, try drilling a couple of holes into the screw far enough apart to match the width of the screwdriver blade you plan to use. Then drill more holes between these two to remove everything. Make sure the bit you use also closely matches the thickness of your screwdriver tip so you have a good fit. An 1/8" deep groove will probably be good, maybe a hair deeper?
If all goes well, I would then turn the screw IN first until lightly seated and clean up the threads as best you can. Then I would back the screw out to where you want it. Just make the new groove right the first time, or you'll most likely be looking for a new carb body.
If you pay attention and "connect" the drilled holes just right, it's easy to make a new groove.

[KEITH KRAUSE]

By the way, is it possible you could post a couple of pic's of your seat?
I think I want to copy that design/shape for my bike. I want to be able to have good enough shots that a shop can copy from the photo. Maybe a side shot or two and one of the top? Greatly appreciated if you can.

[marcovandevelde]

Worked it out!

Hi Keith,
Thanks for your response. I drilled the holes like you suggested, and then hit a small screwdriver in with a small hammer. I was able to get it out a long way, before the head snapped in half. Did it again, and out it came. I will send you some pictures of the seat, I got a new digital camera last week so I'm able to make close-up shots (3cm. close). I wil sent two different needle shots, as I retreived a needle from a 32 mm GS850 carb that is different in detail.

Thanks again, greetz Marco.

[marcovandevelde]

seat?

Hi again Keith, I suddenly realise you weren't talking about the needle seat but the seat on the bike. This pic is not my bike I have to admit, but I do have some other pictures of it that give a good view on the seat. Like I said I got a digital camera last week so now I can fit in a picture of my bike, which looks very similar but is blue and white like the Wes Cooley GS thou. I have a Guiliari seat on, want pictures of that too?

Marco.

[KEITH KRAUSE]

I'd appreciate any pic's you can post.
Glad you got the screw out. I hope you have another one.
I did'nt mean for you to drill the new notch and then hit the screwdriver blade into it. That probably stressed the screw even more. I just meant to make a new notch that would fit your blade well. And from your description, you moved the screw out instead of in first and cleaning up the threads. But as long as it worked, I'll let others know about this method. Nobody has posted trying to remove screws this way.

[marcovandevelde]

mixture screw

Hi Keith,
I did screw it in first to clean the thread a little, but I didnt want it to stay in there in the shape it was in now. When you have drilled the holes, it doesn't take much force to tap the screwdriver in, there are only small bridges left. I do have some needles from a 32 mm cv mikuni that look very similar, but think I'm going to clean the thread first if I can find a suitable cutter.

You'll find the pictures in the mail shortly.

Greetings, Marco.

[KEITH KRAUSE]

Make sure the new screw is the same length and tip diameter or you'll never be able to tune it right. (But you probably know that.)