Questionstarts fine but will not take throttle load also appears to be running rich how do i lean mix
AnswerRandy... early model Hawk series bikes had a lot of issues with stator/pulse generator coils, which can cause low-voltage output from the coil.
Sometimes, when an engine will idle, but not take throttle above idle, then the coil is bad/weak or there is no spark advance through the CDI module. Not saying that this is your problem, but if you clean the carbs and don't find any thing that looks worn/plugged up, then consider checking the ignition system, including the spark advance.
If you go into the carb set, then get packing gasket sets, so you have what you need when you go inside the bowls.
http://www.cmsnl.com/honda-cb400t-ii-1979-general-export-mph_model15775/partslis...
There is an air-cut valve on the side which can fail at the diaphragm, causing idle mix issues/air leak/backfires, etc.
On some models, the primary main and secondary main jets were the same size and were inadvertently swapped causing big richness issues at low speed.
Read the spark plugs to verify richness... black insulators and tips. If they are still white and shiny, then the problem is more likely ignition than fuel. The only adjustment you can make on the carbs is the idle mixture screw (once the limit cap is removed). Look for a dislodged needle in the carb slide, if it is a one-sided problem.
Bill Silver
