I'll search around here but I figured I should start a thread on this as well; my GS doesn't run right after rebuilding the carbs. Not sure what's wrong, I'm using a test tank made from a coolant bottle and that seems fine, got the carbs on last night and double checked everything this morning. I'm using #150 main jets, #40 non-bleed primary jets, and I'm running a full V&H exhaust + K&N lunchbox. Bike is a 1992.
Right now the thing doesn't idle below about 4700 RPM. I figured vacuum leak but it's kicking out smoke that smells of fuel from the exhaust when I've run it. Starts right up needing no choke so it really does seem rich to me. I had the idle mix screws turned out 3 rotations, on a hunch I seated them, bike runs about the same. What did I miss or break, etc, to cause this?
Thanks.
Something else that's going on; at this crazy idle, there's light amounts of smoke coming out of the K&N. I've pulled the throttle cable completely loose to make sure it wasn't holding the plates open, didn't affect it. Make sure vacuum caps were on both carbs tightly (not using frame petcock right now) and there's not much else on the bike that could be leaking vacuum...
Marking this for the future; when pulling the carb off, and you come back with a wicked high idle that seems fairly smooth and not very erratic, check the bloody cables. I just yanked everything loose and it seems that the throttle and choke were both behind held open.
Sweet, sweet progress.
Yes, I had the same problem. It turned out to be the throttle cable in my case, but an overtight choke cable would do exactly the same thing. Glad you got it sorted!
-M