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3.8 EXHAUST SYSTEM
Before every test, make sure that the springs are well hooked and properly in place. In
case of breakage, replace the broken spring. Never race the kart without the 2
springs in place, as otherwise the exhaust pipe could vibrate beyond control.
Every 10 ÷15 hrs, open the pipe end and make sure that the holes on the internal
counter cone are not plugged.
The equipment muffler has already been tuned to achieve the best possible
performance.
Having fixed a sprocket ratio, it could be necessary to improve the engine performance
either at low or at high RPM. This could be achieved by modifying the suggested
exhaust length, removing or adding the spacers placed behind the exhaust header.
In general, by shortening the total length, an improvement at high RPM is achieved,
and vice versa, by lengthening it, the low RPM is improved.
When testing, though, never exceed in lengthening or shortening by more than 5mm
per time.
3.9 EXHAUST VALVE ADJUSTMENT GUIDE
The engine is provided with a pneumatic power-valve on the exhaust duct to improve
the performance at low RPM.
The power valve can be adjusted by turning the ring nut or by replacing the retaining
spring inside the power valve.
The basic setting varies according to the spring type and is achieved by turning
clockwise the ring nut until limit stop and then unscrewing and counting the number of
notches necessary until you get an optimal setting.
-
Ø 0.9mm / L=45mm spring wire: from the limit stop, unscrew the ring nut by 2 notches
(all versions).
-
Ø 1mm / L=43mm spring wire : from the limit stop, unscrew the ring nut by 15 notches
(all versions).
5mm SPACER
(ONLY F1 - F2 - F4)
29
MAN-051 ING
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