3-10 ENGINE TOP END
Clean Air System
Seat (see Frame chapter)
Fuel Tank (see Fuel System chapter)
Pull off the hoses [A] from the air suction valve cover, air
cleaner, and carburetor vacuum hose joint.
Take off the vacuum switch valve [B] with the hoses.
Vacuum Switch Valve Installation
the vacuum switch valve so that the air hole [A]
Route the hoses correctly (see the General Information
Vacuum Switch Valve Test
. Remove the vacuum switch valve.
Connect the vacuum gauge [A] and syringe [B] to the vac-
uum hoses as shown.
Air Flow [C]
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 rises to 57
65 kPa (430
490 mmHg, 8.3 - 9.4 psi), it should stop
air flow. When the vacuum is high enough, the air cannot
flow th rough the valve.
Low Vacuum 
Secondary Air Flow [E]
If the vacuum switch valve does not operate as described,
replace it with a new one.
To check air flow through the vacuum switch valve, just
blow through the air cleaner hose.
Vacuum Switch Valve Closing Pressure (Open ---+ Close)
65 kPa (430
490 mmHg,8.3- 9.4 psi)
Secondary air cannot flow [B]
GE040 1065 1 C