Where are you adjusting the Idle Speed?
Your original post mentions using a CABLE TYPE Adjuster?
There should be a Spring Loaded (to hold tension) Idle Speed Screw on the end of the Throttle Plate Shaft.
That is where the Idel Speed is adjusted by opening the throttle plates directly at the shaft.
1970 CB 350 CAFE - Current Project on the bench,
1972 CB 350 K4 Red - Now a Happy Rider ! !
1972 CB 350 K4 Green (My Sons) DONE - YES !,
1st Bike 1970 SL 350 (Brought home in Parts - Trailer/Trunk/Back Seat - I miss that bike),
2nd - Bike Kawasaki 750
3rd - '73 XLCH 1000