Here are some of the differences between the various factory carburetors on the Honda CX500, GL500, CX650 and GL650 motorcycles.
From the front (engine side):
CX500 (excluding E):

GL500 and CX500E Sports (no accel. pump on photographed carb):

CX650C, CX650E, GL650, ’83 CX400 Custom:

From the rear (airbox side):
CX500 (excluding E):

GL500 and CX500E Sports (no accel. pump on photographed carb):

CX650C, CX650E, GL650, ’83 CX400 Custom:

From the top:
CX500 (excluding E):

GL500 and CX500E Sports (no accel. pump on photographed carb):

CX650C, CX650E, GL650, ’83 CX400 Custom:
