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Ø0.9mm / L=45mm
2 NOTCHES
Ø1mm / L=43mm
15 NOTCHES
NOTE ON THE PNEUMATIC POWER- VALVE OPERATION
The power-valve chokes the exhaust port opening at low RPM, and achieves a more
limited port timing diagram and a reduced exhaust port. The power valve function is to
optimize the engine performance up to a given RPM. Above this RPM, the power-valve will
open to re-establish the original port timing, in the mid-top RPM range. For the
REEDSTER engine, the opening RPM is set at approx. 9500 RPM.
In addition to the above, we can give a few recommendations to the driver for the proper
adjustment of the power-valve. In any case, such a procedure can also be followed to for
the best opening RPM setting.
• If the power-valve opens too soon, that is, below 9500 RPM, the driver will feel a
power output discontinuity, just under this speed limit.
In this case screw (clockwise) the adjustment ring nut on the power-valve, one
notch at a time, until the phenomenon disappears.
• If the power-valve opens too late, that is, over 9500 RPM, the driver will feel a
power output discontinuity, above this speed.
In this case, unscrew (ccw) the adjustment ring nut on the power-valve, one
notch at a time, until the phenomenon disappears.
The adjustment of the opening speed must be performed when the engine is warm and
working at standard operation temperature.
When the engine is cold, as it normally happens between two working sessions, the oil
residuals, which are present between the exhaust valve and its seat, reach a higher
viscosity and this prevents the valve operation and delays its opening. This situation can
be experienced when the engine has not reached its operating temperature, and this
situation can be corrected, by slightly unscrewing the adjustment ring nut. We suggest
though not to modify the setting, as, once the engine reaches the proper working
temperature, the oil becomes more fluid and the valve starts working again properly ;no
other intervention is required .
30
MAN-051 ING
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