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How to remove the Keihin carb ACVs or air cut off valves - Honda CX500, GL500, CX650, GL650

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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.