The air cut-off valves are located on the side of each carburetor; they’re on the same side of each carb and are held in by two small bolts:
While one is on the outside and easily accessible, the other is inbetween the two carbs and will require a right angled or short driver for the Standard/Shadow/Custom CX500 variants. It’s a bit more challenging for the GL500, CX500E or 650 variants due to the difference in shapes of the carbs:
If you are separating the carbs to clean them then you don’t need to worry about putting yourself through the hassle of removing the ACV on close-fitting carbs as you can simply do it once you have split the two carb bodies. Again using a good screwdriver, remove the two bolts – there’s a spring under here so keep some pressure on the plate to prevent it from flying out. There’s also a tiny O-ring under there that you don’t want to have vanish so be vigilant when taking it off:
Bolts removed – part number
This particular cover was firmly stuck on:
Spring:
This one had been glued together – a sign of a previous owner trying to fix a problem. Don’t glue a broken diaphragm, replace it.
The O-ring was stuck to the cover – it could be here or stuck to the carb body:
Note that there’s a bevel on one edge – that side faces into the carburetor:
We’re going to use another set of carbs for photos of the diaphragm as this one was siliconed together and rendered useless;
Underneath the diaphragm – there’s remnants of the old glued in diaphragm around the edges:
Other photos of a better example to come. Click here to go back to the main Honda CX500 carb cleaning page.