Section 03 787 RFI ENGINE
Subsection 03 (TOP END)
GENERAL
The 2-stroke ROTAX engine rotates counterclock-
wise seen from the rear (PTO flywheel).
The 787 RFI engine has a rotary valve to control
opening and closing of the intake and it is also
equipped with the Rotax Adjustable Variable Ex-
haust (RAVE) system.
RAVE System
(Rotax Adjustable Variable Exhaust)
BASIC OPERATION
The RAVE valves change the height of the exhaust
port. The RAVE valve solenoid, which is controlled
by the Engine Control Module (ECM), allows posi-
tive crankcase pressure to inflate the bellows and
open the RAVE valves.
On 787 RFI engine, the RAVE valves are controlled
by the ECM.
To open the RAVE valves, the ECM activates a
solenoid which directs the positive pressure from
engine crankcase to the valves.
2
F06D3BA
1
3
TYPICAL
1. Solenoid
2. Pressure hose from crankcase
3. To atmospheric pressure
NOTE:
A check valve on the pressure line elimi-
nates the negative pressure from the crankcase.
To close the RAVE valves, the ECM deactivates
the solenoid which blocks the crankcase positive
pressure. The RAVE valves are opened to the at-
mosphere.
3
F06D16A
2
1
4
5
RAVE VALVE OPENED
1. Pulse from crankcase
2. Check valve
3. Positive pressure to solenoid
4. Solenoid activated
5. Positive crankcase pressure to RAVE valves
3
F06D16B
2
1
4
5
RAVE VALVE CLOSED
1. Pulse from crankcase
2. Check valve
3. Positive pressure blocked by the solenoid
4. Solenoid deactivated
5. RAVE valves are opened to atmosphere
ADJUSTMENT
On top of the RAVE, there is a red plastic ad-
justment knob. Turning the adjustment in or out
changes the preload on the return spring which,
in turn, will change the RPM at which the RAVE
valve opens and closes.
smr2005-082
73
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