650LK (Turbo)

LUBRICATION SYSTEM

The turbo unit is pressure-lubricated from the main engine oil gallery. A check valve is installed on the outlet o' the engine main oil gallery to stop oil flow to the turbo unit when the engine is not running. A scavenging pump rotor is equipped behind the original oil pump rotor to retrieve the oil from the turbo unit, ensuring a constant flow of oil.

Check valve opening pressure: 24.5 kPa (0.25 kg/cm , 3.56 psi)

CARBURETOR

The carburetor is a fully-enclosed type BS30; float chamber ventilation is opened to the surge tank, because the float chamber must always be under boost pressure in order to supply sufficient fuel to the venturi.

CARBURETOR SECTION VIEW

FUEL PUMP

The fuel pump is operated by a DC motor that is directly coupled to the pump. Fuel from the fuel cock is drawn into the pump, flows around the motor to the outlet at the opposite end of the housing, and then is fed through the check valve.

FUEL SYSTEM COMPONENTS

NOTE:

1. Connect fuel hose 1 to the fuel cock "OUT".

2.  Connect fuel hose 6 to the fuel cock "IN".

3.  The center mark on the fuel pump should be located in the upper center of the damper stay as shown in the illustration.

INTAKE SYSTEM

The intake system consists of an air cleaner, a surge tank, a reed valve, and a relief valve. All work together to provide the correct amount of air over the entire range of the engine's performance requirements, from low to high speeds.

SIDE VIEW

REASSEMBLY

CAUTION:

The exhaust system operates under very high pressure from the turbocharger. Every connection and joint in the system must be tight, and new gaskets must be used. There must be no exhaust leaks or a drop in performance will result.

INSPECTION

Turbocharger

1. Ensure that the turbine and compressor rotors turn smoothly.

2.    Ensure that the actuator valve and waste-gate assembly operate correctly.

3.    As the turbine is turned it should not bind at any point, there should be no side play, and there should be no axial play in the turbine/compressor shaft.

EXHAUST SYSTEM

The exhaust system is composed of exhaust pipes, an exhaust chamber/turbocharger assembly, and mufflers. The turbocharger is operated by the engine's expelled gases and this in turn operates the compressor rotor, which creates the boost pressure for the combustion chambers. The boost pressure is controlled by a wastegate that channels unneeded exhaust out the right hand muffler. See the block diagram below.

LOCATION AND OUTLINE OF TURBO SYSTEM COMPONENTS

MAJOR COMPONENTS OF THE YAMAHA TURBO SYSTEM