Rc Valve - Honda CR250R Owner's Manual & Competition Handbook

Refer to Safety Precautions on page 19.
The exhaust valves open and close according to
engine speed to ensure sufficient torque
throughout the entire engine rpm range. The
valves should be fully closed at low rpm and
fully open at high rpm.
The exhaust valve system is a precision
assembly. Before beginning
inspection/decarbonizing, please study the
following text and illustrations carefully.
Before attempting complete disassembly, we
recommend you consult the service manual or
your Honda dealer. Mismatching of parts on
reassembly can measurably affect engine
performance.
Operating Inspection
Before inspection, clean the engine thoroughly to
keep dirt from entering the engine.
1. Warm up the engine to operating temperature.
2. Stop the engine, and remove the RC valve
cover.
3. Connect the tachometer.
4. Start the engine and check that the RC valve
pulley (1) is in the fully closed position.
5. Increase the engine speed until about 8,000
rpm and check that the RC valve pulley turns
to the fully open position.
(1) RC valve pulley
6. Disconnect the cables from the RC valve
pulley. Check that the exhaust valve turns
smoothly. If the exhaust valve does not turn
smoothly, remove the exhaust valve and
decarbonize the RC valve (2) and valve shaft
assembly (3).
(3)

(2) RC valve

(3) valve shaft assembly
Exhaust Valve Removal
1. Remove the cylinder (page 50).
2. Remove the socket bolt (1) and stopper plate
(2).
(2)
(1) socket bolt
3. Remove the valve shaft assembly (3) from the
(1)
cylinder.
4. Remove the cylinder cover (4) by removing
bolts A (5) and bolts B (6). Remove the RC
valve (7) and O-rings (8).
(7)
(4)
(5)
(2)
(6)
(3) valve shaft assembly
(4) cylinder cover
(5) bolts A

RC Valve

(1)
(2) stopper plate
(8)
(3)
(6) bolts B
(7) RC valve
(8) O-rings
55
Servicing Your Honda