Idle Speed and Idle Adjustment Screws

[bornfrustrated]

Hey all,

I've noticed my bike's idle seemed off. It didn't seem as smooth as it should so I've been looking into the synchronizing the throttle bodies (which seems to be a misnomer since the adjustment for synching them shouldn't be touched...?). I made a manometer similar to this one , and when I first checked the readings on it, cylinder 3 fluid was much lower than 1 and 2. As I adjusted the idle adjuster screws (brass) for each I was able to pull the vacuum levels closer, but it seemed to run worse once they pulled the same vacuum.

So I started to make sure the throttle position sensor was set right. Seems like to set it there should be a click just as the throttle is turned and at full. I don't get another click at full throttle. Still didn't seem right to me.

I tried to start from scratch so I lightly tightened the brass screws then backed them out 1.5 turns. I set up the manometer and adjusted from there. They're closer than before but idle is no better than when I started. I had to raise the base idle screw once I did this because it was idling low at 850 (1000 range now).

I also saw a thread that someone set cylinder 3 idle screw 1.5 out from bottom and then only measure cylinders 1 and 2 to pull the same regardless of cylinder 3.

I sprayed some starting fluid around to see if there were any leaks and I got no increase in idle from the bike at any point. I feel like I missed the order things should have been done and ended off worse than before. How do I get back to a base for checking the idle for adjustment?

[The Mighty Gryphon]

I also saw a thread that someone set cylinder 3 idle screw 1.5 out from bottom and then only measure cylinders 1 and 2 to pull the same regardless of cylinder 3.

Are you sure that is what was said in that thread?  If you have a two inlet vacuum balancer, you set either cylinder #1 or #3 for 1.5 turns out and match the other two to that cylinder. 

Another cause of rough idle is cracks in the crankcase breather tube A.K.A. the "Z" tube.  They are well known for cracks that allow leaks where the hose clamps are attached.

Has the bike been idle for a long period?  It's possible that the injectors are varnished up internally and sticking.  A tank of fuel with a bottle of Chevron Techron Fuel System Cleaner and a good hard ride will help loosen them up.

[bornfrustrated]

I try to ride the bike often during the summer so it hasn't been sitting. I did notice the z tube was cracked this spring and I replaced it a couple months ago. I'm not sure what you mean by the first line. If I'm only measuring #1 and #2, how would I know when they match #3 if it's not being measured? Do you mean just not touch the #3 idle adjustment screw and only adjust #1 and #2 until they match whatever #3 is pulling?

If it's not set right am I gonna be looking at any major problems sooner or later on other than poor idle/fuel economy/power?