Removing the cover screws It has come to my attention that my Maintenance tutorial, Carburetor Disassembly, Cleaning, Reassembly doesn't mention the "Air Cut Valve" assembly, a component of the 3d- and 4th-gen VFR carbs. Let's have a look.
The valve's function, as I understand it, is to prevent popping on deceleration (closed throttle). The casting is present on the 2d-gen carbs but is not used. I assume the valve was needed because of the additional emissions hardware present on the later models.
We begin by removing the two cover screws. Inside we find a strong spring and the metal/rubber diaphragm (below). The diaphragm is usually slightly stuck in place, and rather than risk damaging the rubber, I use a small magnet to gently pull it free.
(click on an image to enlarge)
The valve's function, as I understand it, is to prevent popping on deceleration (closed throttle). The casting is present on the 2d-gen carbs but is not used. I assume the valve was needed because of the additional emissions hardware present on the later models.
We begin by removing the two cover screws. Inside we find a strong spring and the metal/rubber diaphragm (below). The diaphragm is usually slightly stuck in place, and rather than risk damaging the rubber, I use a small magnet to gently pull it free.
(click on an image to enlarge)
Note the oval o-ring pictured here.
These parts are no longer available from Honda but aftermarket kits are available. However, your parts are reusable if undamaged, so handle with care. Gently remove this o-ring for safekeeping during cleaning.
These parts are no longer available from Honda but aftermarket kits are available. However, your parts are reusable if undamaged, so handle with care. Gently remove this o-ring for safekeeping during cleaning.
I wash the parts by hand and blow the air passage clear (arrows) with compressed air, along with the two passages in the carb body.
Reassembly is simple, but that's a strong spring to hold pressure on while locating the screws.
Reassembly is simple, but that's a strong spring to hold pressure on while locating the screws.
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