Purpose, Function
By lengthening the exhaust passage, the transmission of exhaust pressure waves to other cylinders can be delayed, and the amount of gas exhausted from a cylinder and forced back inside the combustion chamber is reduced By reducing the residual gas, the temperature inside the combustion chamber is reduced and the occurrence of knocking even at a high compression ratio is inhibited.
Construction
The exhaust manifold is installed to the rear of the engine. In addition, the catalytic converter (WU-TWC) is integrated (WU-TWC).

When the No.1 cylinder is at the intake stroke, the No.3 cylinder is at the exhaust stroke. By inducing the high temperature gas exhausted from the No.3 cylinder into the No.1 cylinder, the high temperature gas in the No.1 cylinder remains. If the amount of residual gas is high, the temperature in the combustion chamber rises and knocking can easily occur. With the 4-2-1 exhaust system, the transmission of exhaust pressure waves between each cylinder is delayed by the long exhaust pipes.

Exhaust System Removal/InstallationFront Accessory Socket Removal/Installation
1. Disconnect the negative battery cable..
2. Remove the front console..
3. Insert a tape-wrapped flathead screwdriver into the gap between the cap tab
and socket.
4. Move the flathead screwdriver in the direction of the arrow (1) shown in the
figure, press the front accessory socket i ...
Precaution
Intermittent Concern Troubleshooting
Vibration method
If a malfunction occurs or becomes worse while driving on a rough road or
when the engine is vibrating, perform the following steps.
NOTE:
There are several reasons why vehicle or engine vibration could cause an
electr ...
Cowl Upper Plate Removal [Panel Replacement]
Symbol Mark
Removal Procedure
1. Drill the 9 locations indicated by (A) shown in the figure.
2. Drill the 2 locations by (B) from the front wheel housing side shown in the
figure.
3. Drill the 2 locations indicated by (C) from the inside shown in the figure.
4. Remove the cowl upp ...