Rotax RM1 - Page 120

Operator`s Manual RM1
Seite/page 120/132 ROTAX KART RM1 Ausgabe/Edition 01/2006
6.1.2. Exhaust valve adjustment
For an engine with closed exhaust valve (performance curve 1) and open exhaust valve
(performance curve 2) there are 2 different characteristic curve results (Diagram 2). The optimum
performance characteristics of the engine is achieved when the opening timing of the exhaust
valve is at the intersection of the 2 performance curves.
The diagram depicts the situation for better understanding.
With wrongly adjusted exhaust valve you lose performance and in consequence acceleration
potential (Diagram 2 – gray resp. hatched zone).
If the exhaust valve opens too soon, the engine acts as per performance curve 2 (for open exhaust
valve) which gives less performance at this r.p.m. range, and you loose acceleration potential.
If the exhaust valve opens too late, the engine acts as per performance curve 1 (for closed exhaust
valve) which at this r.p.m. range gives less performance, and you loose acceleration potential.
The engine reaches maximum performance even with the exhaust valve wrongly adjusted, but you
loose performance and thus acceleration potential.
Diagram 2
Leistungsverlust bei falschem Schieberöffnungspunkt
Performance loss at wrong exhaust valve timing
0
2
4
6
8
10
12
14
16
18
20
22
24
26
4.000 5.000 6.000 7.000 8.000 9.000
10.000 11.000 12.000 13.000 14.000
Motordrehzahl [1/min.], engine revolutions [rpm]
Motorleistung [kW],
performance of engine [kW]
optimaler Schieberöffnungs-
zeitpunkt / optimum valve
opening point
Schieber öffnet zu
früht / valve opens
too early
Schieber öffnet zu
spät / valve opens
too late
Leistungskurve 2
performance curve 2
Leistungskurve 1
performance curve 1