Carburetor Synchronizing

Posted by RodneyCB750K1979 on
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/Carburetor-Synchronizing-tp4044371.html

I'm getting a lot of cam chain noise at idle so I thought to check the carb sync.  It was off as shown in first  photo.  I adjusted #1 to match #2.  Then #3 to match #4. See second photo. When I try to bring #3 and #4 to match #1 and #2, the idle rose to 2,500 rpm.  I adjusted the large black knob underneath the carbs to lower the rpm but it won't go below 2,000 rpm. I made sure the choke was off.  Is there some other adjustment I need to make?  Could the choke idle lever need adjusting?  

Also, how the heck does one adjust the #2 and #3 idle mix screws underneath the carbs?  

Carb sync as-found


Left and Right Pairs synchronized