Hardening, shrinkage, or damage of both gaskets and O-rings after disassembly can reduce sealing performance.
Remove old gaskets and clean the sealing surfaces thoroughly so that no gasket material or other material remains.
Install the new gaskets and replace the used O-rings when re-assembling.

Force
Liquid Gasket, Non-permanent Locking AgentParts Removal/Installation
WARNINGGasoline is extremely flammable and can be
explosive
under certain conditions. Turn the ignition
switch OFF. Do not smoke. Make sure the area is
well-ventilated and free from any source of flame
or sparks; this includes any appliance with a pilot
light.
NOTICE
...
Air Cleaner Housing Removal
Remove the fuel tank (see Fuel Tank Removal).
Disconnect the secondary fuel hose [A] from the delivery
pipe of the nozzle assy [B] (see Fuel Hose Replacement
in the Periodic Maintenance chapter).
Disconnect the secondary fuel injector connectors [C].
Free the lead from the grooves [D].
...
DFI System Wiring Diagram
Part Names
1. Air Intake Solenoid Valve (Other than US, CA and CAL Models)
2. Front Wheel Rotation Sensor
3. Engine Stop Switch
4. Starter Button
5. Air Switching Valve
6. Stick Coil #1, #2, #3, #4
7. Spark Plugs
8. Intake Air Temperature Sensor
9. Crankshaft Sensor
10. Secondary Fuel ...