Over time, air cutoff valves will harden up, perforate and/or disintegrate leaving your bike in a permanently lean, low RPM range (0-2200). When this occurs, your bike will progressively require excessive choking on warm-up and will miss during idling, miss and backfire when throttling up or down, and/or hesitate and backfire when trying to accelerate quickly. This condition will eventually cause "after burn" generated by a lean fuel mixture when closing the throttle.
An alternative to purchasing the costly OE assembly is our inexpensive air cutoff valve kit and, at the same time, replace your inexpensive carburetor manifold o-rings to insure against any additional vacuum loss.
INSTALLATION: Refer to your Clymer, Haynes or Honda Workshop manual for location and installation procedures.
Air/fuel mixtures must be set with use of mercury or vacuum gauge carburetor synchronizer. The mercury sync tool, or carb stick, are the most accurate as they are all set by sight using the number 3 carburetor as the reference level. The number 3 carb is the constant fixed flow carburetor set at the factory.
DO NOT attempt to set by ear or just by guessing as the results can be anywhere from pathetic to disastrous.
DO NOT deviate from the book settings. Wiser people than all of us designed this very, very effective and efficient intake and carburetion system.
To further insure against any additional vacuum loss, replace your inexpensive carburetor manifold o-rings, 82-610 (GL1000/GL1100) or 82-611 (GL1200). Vacuum loss can occur there and mimic the effect of a bad air cut-off valve. Paste a new set in with petroleum jelly and make sure they are sealed with an ether check.
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