Need help identifying screw and what it does

[Guest]

I am 100% new to motorcycles in general, and even newer to this forum. I apologize in advance if posting this is against any rules, although I did read the FAQ. I recently purchased a 1978 GS550E that is running and riding OKAY, but it does have a few problems. One of the problems that I just ran into is in identifying the function of a screw that is in the slot in the choke. I've posted the best picture I have as I don't keep the bike with me. The screw is towards the top of the picture with the choke. What does it do? I think it is responsible for the incredibly high idle RPMs I've been having. Is it the idle screw. If so is it supposed to have a tip on the inside because it does not. IMG_20161120_105019.jpg

[Big T]

It applies tension on the choke lever to hold said lever in place.

It is not responsible for your high RPMs unless it's so tight the choke won't shut off

[steve murdoch]

Welcome to the wonderful world of the GS.
Your idle adjustment will be a knurled knob at the top of the carbs in the middle between carbs 2&3.
A complete carb clean might be in your future. That process and a ton of other fix-its can be found here. http://members.dslextreme.com/users/bikecliff/ t

[Nessism]

Good luck with your new toy and please check the Newbie Mistakes thread linked in my signature. Your bike needs some maintenance.

[roeme]

the incredibly high idle RPMs I've been having.

Now that I see the picture...what steve said: It's likely your carbs and/or the intake boots. You can check the idle adjustment screw (as said between carb 2 and 3), but I doubt that it makes much of a difference. It looks like at least one of the carbs has been overflowing for some time now.

Seems to be your first bike. In this case I especially recommend:

1. Read the top 10 newbie mistakes thread here.
2. Download the manual for your bike from http://members.dslextreme.com/users/bikecliff/ and stick your nose in it.
3. Check the Valve clearances, or have them checked.
4. Check the charging system with the help of posplayr's quick test thread, here.. The stock R/R is known to fail over time.
5. Prepare yourself for a carb cleaning, and do it.
6. Take it from there.

[DumbGenius49]

Thank you for the links and the great info guys. Everything you link, I'll be checking out and I guess I'm going to ready myself for a carb cleaning.