Section 04 ENGINE
Subsection 01 (593, 593 HO, 593 HO SDI AND 793 HO ENGINE TYPES)
TROUBLESHOOTING
Before completely disassembling the engine,
check airtightness. Refer to LEAK TEST AND
ENGINE DIMENSION MEASUREMENT.
COMPONENT REMOVAL WITH
THE ENGINE INSTALLED
Most engine components can be removed with
engine on vehicle such as:
– cylinder head cover no. 1
– cylinder head no. 2
– cylinder(s) no. 3
– piston(s)
– piston ring(s)
– rewind starter
– oil pump
– water pump
– magneto flywheel
– RAVE valve(s)
– reed valve(s).
CLEANING
Discard all gaskets and O-rings.
Clean all metal components in a non-ferrous metal
cleaner.
Scrape off carbon formation from cylinder ex-
haust port cylinder head and piston dome using a
wooden spatula.
NOTE: The letters «AUS» (over an arrow on the
piston dome) must be visible after cleaning.
Clean the piston ring groove with a groove cleaner
tool or with a piece of broken ring.
RAVE VALVE BASIC OPERATION
SDI Models
The RAVE valves change the height of the exhaust
port. The RAVE valve solenoid, which is controlled
by the ECM, allows positive crankcase pressure to
inflate the bellows and open the RAVE valves.
To open the RAVE valves, the ECM activates a
solenoid which directs the pressure to the valves.
1
A32C94A
1. Pressure from solenoid
1
A32C95A
3
4
2
1. Solenoid
2. Pressure to RAVE valves
3. Vent to throttle body
4. Pressure with check valve from crankcase
To close the RAVE valves, the ECM deactivates
the solenoid. The RAVE valves are opened to the
intake manifold.
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