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 AgentESD (Electronic Steering Damper) ECU Error (Service Code E3b, ZX1000JD/KD)
If this service code appears, check that the following parts
are correctly.
Crankshaft Sensor
Gear Position Switch
Starter Lockout Switch
Main Throttle Sensor
Rear Wheel Rotation Sensor
If these parts are normal, check the ESD ECU for its
ground and power supply (see ESD ECU Power Supply
...
Air Cleaner Housing Installation
For ZX1000JD/KD, be sure to install the pad [A].
Install the clamp bolt heads [A] inside as shown in the
figure.
Install the air cleaner housing on the throttle body assy.
Push in the ducts [B] touch the stoppers [C] of the throttle
body.
Be sure the hoses are routed correctly ...
Brakes
Brake Wear Inspection
Inspect the brakes for wear. For each
front and rear disc brake caliper, if the
thickness of either pad is less than
1 mm (0.04 in.), replace both pads
in the caliper as a set. Pad replacement
should be done by an authorized
Kawasaki dealer.
A. Lining Thickness
B. ...