1980 CB750K Carb Issues

Posted by rhinocb750k on May 28, 2013; 5:03pm
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/1980-CB750K-Carb-Issues-tp4041372.html

Hi guys, looking for some help.

I have had my bike for a couple years with no issues.  My problem started with a needle valve issue with fuel coming out of the overflow.  I decided at that point to do a cleaning of all 4 carbs (bank assembled) and new needle valves.  After cleaning I decided to include the air cut bypass during assembly.  I backed out the pilot needle 3-1/2 turns.  Bike Runs but is lean at idle even after warm up.  I checked for leaks at the intake boots but found none.  At this point i figured there must be something clogged in the fixed idle jet.  Removed the carbs again and cleaned them again and made sure I could run a wire down the fixed passage and blow cleaner through the circuit.  I reinstalled them and had the same problem.  Bike is lean.  No matter how much I back out the pilot needle it is lean.  Any ideas to my problem.  The only thing I changed is the air cut bypass.  Should I not bypass the air cut?  Anyone else had this problem?  Any help would be appreciated.  Thanks


-stock jets 68 primary, 102 secondary
-stock air box/filter
-exhaust is stock 4x4 but previous owner cut most of the mufflers off