This weekend I shot my idle mixture screw out of the carb while trying to get up to highway speed on an on-ramp. At first I though my manifold had loosened and starting letting in to much air as my carb immediately started coughing. Had to ride home fully choked and pull the carb off to find I had no mixture screw anymore. I have ordered a replacement thumb screw style from Yost but am a little worried this can happen again? Has this happened to anyone else?

 

First time I have ever heard of that happening. Did it strip the threads in there?

Griz

 

While they didn't look noticeably stripped in my dimly lit garage I can't help but think they have to be. If it slowly vibrated out I would have weeks of poor performance. Although, maybe I did. I tend to overlook the little minor issues on the Harley as part of owning an Evo.

 

Usually the spring tension will hold it in place. Like I said, first time hearing of it.
Griz

 

That's a weird one.

Have you been in there before? Are you sure some previous owner didn't install it without the spring?

 

I have not actually. I bought it from Ebay and changed the jets but as I did not order the thumbscrew all I did was seat the screw and back it out for tuning. Emissions plug was already out when I bought it so it could be a possibility.

 

when we see the screw loose like that one was we use a little silicone on the end once we have the carb dialed in / just squeeze a ball on the end and let it dry overnight

 

Sometime in the previous lives of my Super Glide someone put in a thumb screw A/F screw. They did something brilliant by putting a hose clamping a piece of stiff wire on the carb that rubs against the thumb screw, working as a rachet. The screw can't fall out.
I'll post a picture if anyone's interested.

 

I'd be interested to see it.

 

There it is. Pretty simple.