Air Screw stuck, HELP!

[Roemy24]

I'm need of some expert help and you all seem very knowledgeable. Early this spring I reintroduced myself to the GS line with a 1980 GS850L. The bike needed a little work but after tearing into I see that I've been took.

It wouldn't idle right without the choke and when you tryed rev'n it, 1200RPM is all it would do before wanting to die. I decided to look into the carbs even though he said they were cleaned last fall. After a whole weekend of heads stripping on me and anything that could be more difficult that it had to be happened. Make a long story short they were extremely dirty. I removed everything to dip the parts in cleaner and also got new kits to replace practically all the parts. However....HOWEVER the air screws wouldn't turn out. I ground down a flat screw driver to fit the hole so it was a good fit. Had carb cleaner sprayed in it to help loosen them but two wouldn't turn, one turned some, and the other half I guess. I can't get them out. :shock: Can I drill them with a press slowly to help relieve the presser (I know this is could turn out dangerous) but I didn't know there was a o-ring in there which is probably shot now that they've been cleaned. I'm on the verge of stripping the slot on the air screw and don't want to try anymore without some tips.

PLEASE help!

[chef1366]

Soak PB Blaster in there for a couple of days. If still a no go I cut the tunnel to the screw off with a dremmel and then cut a slot in the head. Sounds scary but it works. Just don't cut the slot so deep that you ruin the threads.

[cmart45]

stuck pilot screw

.
The factory pre set air jet screw hidden on the top outlet side of the carbs can also be rusted and clogged with gunk. Drill out the tab with a 1/6" drill to screw a small sheet metal screw into the tab to pull out the plug with pliers. Be carefull not to drill too deep.No more than 1/8",not to damage the needle.Take a good qaulity flat head screw driver to remove.Some penatrant and patience working it slowly back and fourth till it losens up to unscrew all the way out.The best stuff I like to use to losen rusted bolts,is "Freeze off" from OREILY. If you have heads bolt nuts that are stuborn,try "Freeze off"!
You will be amazed! Follow the instructions on the can(very important)

[hikermikem]

I've had good luck using a heat gun to expand the alum carb hsg around the screw. The alum expands more than the steel as it heats up so it "should" release the hold on the screw. It's worked for me in the past on a couple of air mix screw that had me, well, ... screwed.

Note, I'm not talking a hair dryer here, you need a heat gun. They are available at harbor freight & most good harware stores I would think. Be patient & use a GOOD fitting screw driver, Whacking the screwdriver a few times with a hammer (like simulating an impact driver) while trying to turn the screw may help also; just don't overdo it - if you break the point off the end of the mix screw & it gets lodged at the bottom of the hole it's bitch to remove.

As chef suggested, use liberal amounts of PB Blaster in addition to the heat gun.

[Roemy24]

I already drilled the cap and used a screw to pop out the cap. So that little chore is done. I'll try the PB Blaster and just to happen to have a heat gun I can borrow from work for the weekend to heat up the casting and hopefully will have some luck. I'll give it shot this weekend. Thanks. Anyother suggestions are more than welcome!

[Ickaruz]

Air Screw

I had the same problem with mine. I destroyed my last carb with an easy out. I hate those things. Anyways, please let me know where you find a new air screw. I have been searching and so far on the internet I have only seen them in rebuild kits and they cost $50 a pop. I hope somebody knows where to buy these things. Thanks for any info and good luck!
Matt

[tkent02]

I hope somebody knows where to buy these things. Thanks for any info and good luck!
Matt

Z1 has them individually.

[hikermikem]

I had the same problem with mine. I destroyed my last carb with an easy out. I hate those things. Anyways, please let me know where you find a new air screw. I have been searching and so far on the internet I have only seen them in rebuild kits and they cost $50 a pop. I hope somebody knows where to buy these things. Thanks for any info and good luck!
Matt

Z1 sells some:

http://www.z1enterprises.com/detail.aspx?ID=2568

http://www.z1enterprises.com/detail.aspx?ID=2569

Call them for more info - they are very nice guys.

[hikermikem]

I already drilled the cap and used a screw to pop out the cap. So that little chore is done. I'll try the PB Blaster and just to happen to have a heat gun I can borrow from work for the weekend to heat up the casting and hopefully will have some luck. I'll give it shot this weekend. Thanks. Anyother suggestions are more than welcome!

HAVE PATIENCE!!! The heat gun will work if given enough time to completely heat up the area around the stuck screw. Be certain the screw driver you use fits perfect, allowing you maximum twisting torque.

As I said , I've used this method before on screws i thought I would have to have drilled out & it worked; just give the process time & keep using the PB blaster.

Good luck

[cbrophy22]

ez-out

I had the same problem with mine after I installed a jet kit. MY two cents if it comes down to using a ez-out. Do not use a round ez-out, Go find a square ez-out. I used a round one, it broke off in the first screw, I went a got a square one that got the others out with no problem. then I had to get a another set of carbs for the one I messed up.

Looking back on it I should have cut the top off like chef said.

Buy the way do any of you know were I can get a (tap and die) set for the idle air screw or what thread size it is?

[hikermikem]

Buy the way do any of you know were I can get a (tap and die) set for the idle air screw or what thread size it is?

I have a tap at home for the mixture screws that came from my '82 GS650 CV carbs (32mm I think). I would guess all the Mikuni CV carbs might have the same mix screw thread.

I think it's 4mm - .50, but I'm not certain. i will check it & let you know. It is a very fine thread for sure. The good news is you can lose a few threads and still have plenty of them left to hold the screw in.