I understand Sierra Electronics may be the repair/tweak outfit you might need.
http://www.sierra-mc.com/I have had the bar mounted control box apart to clean a moisture stain off the back of the display glass (HondaLine Tourer Edition CB). I don't remember clearly, but the "talk lever" may do well with a squirt of electrical spray cleaner internally.
I would try that before sending in it or the main box unit for adjustment/repair.