ENGINE TOP END. Vacuum Switch Valve Test

Clean Air System

Vacuum Switch Valve Test

Using the vacuum gauge and a syringe, inspect the vac­uum switch operation as follows.

• Remove a vacuum switch valve.

• Connect a vacuum gauge [A] and syringe [B] or fork oil level gauge to the vacuum hoses as shown.

Air Flow [C]

Special Tool - Fork Oil Level Gauge: 57001-1290

• Gradually raise the vacuum (lower the pressure) applied
to the vacuum switch valve, and check the valve opera­
tion. When the vacuum is low, the vacuum switch valve
should permit air to flow. When the vacuum raises to the
level shown below, the valve should stop air flow. When
the vacuum is high enough, air cannot flow through the
valve.

Spring [A] Diaphragm [B] Valve [C] Low Vacuum [D] Secondary Air Flow [E]

• If the vacuum switch valve does not operate as described,
replace it with a new one.

NOTE

О To check air flow through the vacuum switch valve, just blow through the air cleaner hose.

Vacuum Switch Valve Closing Pressure (open —> close)
Standard: 45 ~ 53 kPa (340 ~ 400 mmHg)

High Vacuum [A]

Secondary air cannot flow [B].