FAQ4 - How can I improve start and warm up, idling and acceleration?

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 "afterburn" 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.
Click here to find air cutoff valves and o-rings in the Carburetor & Fuel section.

Click here for an indepth explanation.
Click here for Installation.