Idle too high, Suzuki GS405

[Gorminrider]

Ok, so I disassembled the carb again. The choke plunger seems to work fine. However I spotted something I didnt see before. On the left hand side carb the butterfly valve seems to brush against the housing which causes it to not close as tight as on the right hand carb. As you can see in the picture, this is the bottom position, in other words the most closed I can get it. This also causes the other carb to open up just as much when they are linked together. Could this be the cause of the high idle? Or should it be open that much? I'm not sure how closed it should be.

[ATTACH=CONFIG]52323[/ATTACH]

Sounds like you found the problem. Maybe someone actually unscrewed the butterflys from the shaft which is a bad idea....

But to synch the plates, use a gauge wire.

IMO..the reason you use anything at all as a "gauge", to synchronise the butterflies opening is because there's no easy way to tell if they are both exactly closing at the same time and deciding on an opening sliver of light is not easy either...but using a "gauge" as a feeler allows you to adjust too large or too small until you get it very close ... ...it doesn't really matter exactly how thin the "gauge" wire is (something that stays stiff like piano wire is good ) because you will simply adjust idle from the main knob to get it right anyways.

On a twin, retesting synch later with vacuum gauges hopefully will not require big changes -or any at all. If it does indicate large differences, it's telling you there's a problem is somewhere else.

[dbursell]

Okey, a little update. So everything seems to be working properly now and I can get the idle to where I want it to be. The problem was as I mentioned before a misaligned butterfly valve. It would seem as a previous owner has disassembled the valve and when putting it together haven't bothered to align it. The butterfly valve caught in the carb housing, leaving it slightly open, which in turn caused the other carb/side to push open as well. The gap was less than a millimeter but enough to make the idle go to above 3500rpm. You live and you learn. A huge thank you to all the guys here that have taken their time and helped me out with this problem and all the other problems i've had in other threads as well. Very much appreciated. Kudos!