Topic: CB500K1 Keihin 627b choke problem

[hierogk]

Hoping for some help here.  My CB500K1 has started closing its choke all on its own at high rpm's causing the engine to quickly die.  When I run at a steady 5K rpm or above, the engine will suddenly suck the choke plates closed.  It has its original Keihin 627b carbs.  I cannot see any adjustment that would add some friction to keep the vacuum from closing the choke plates.  All ideas are appreciated.

[bryanj]

There should be a steel pin sticking out that locates in two indents in the lever for full open and full closed if the pin or lever get bent enough this dont work

[hierogk]

Thanks for getting back with me on that.  The pin is there and the arm has the 2 detents.  When I push the arm down to open the choke, it stops at its detent.  The arm also stops in the proper spot when I move it up to close the choke.  The problem I have is that, with very little force applied to it, the arm will pop upward to the closed choke position.  I can just flick it with a finger and it will spring up and close the choke.  The resistance is so small the vacuum from the engine can pull the flaps closed.
Is there an adjustment to tighten up the resistance?

[jaytee-nz]

On the end of the shaft that the choke lever is attached to, is a nut. It's difficult to get to, but try tightening that nut to increase the tension on the shaft.