1. Disconnect the tubes from the 2-way valve side and the carbon filter side, connect the hand vacuum pump to the carbon filter, create a vacuum and make sure air passes.
2. Check the tubes for damage and secure connections.
Checking the 2-way valve
1. Connect a hand vacuum pump to the 2-way valve on the fuel tank connection side, create a vacuum and check that air passes.
If air does not pass or the valve itself is leaking, replace the 2-way valve and retest.
2. Connect the air pressure side of the hand vacuum pump to the 2-way valve on the fuel tank connection side, build up pressure and check that air passes.
If air does not pass or the valve itself is leaking, replace the 2-way valve and retest.
(The article was copied from the website: hondabook.ru)