Choice Of Gear Ratio - Rotax Rm1 Benutzerhandbuch

6.1.3. Choice of gear ratio

The 125 Max DD2 engine in spite of its 2 gears offers a broad performance band. Therefore the
frequent changing of gear ratios, as you are used to with 1-speed engines, is not necessary.
Note:
On most of the Kart circuits you will be well served with the standard gear ratio (35 : 62 which is
equivalent to 12/90 for 1
If due to the special shape of the circuit (e.g. extremely sharp corners or long straights) it should
seem necessary, the gear ratio can be changed both to a shorter or a longer ratio.
The diagram (acceleration potential) depicts that the engine has its optimum acceleration potential
between 9.200 and 12.200 r.p.m. /min. It should therefore be operated in this range, overreving up
to 13.600 r.p.m. is possible.
Motordrehmoment [Nm],
torque of engine [Nm]
26,00
24,00
22,00
20,00
18,00
16,00
14,00
12,00
10,00
8,00
6,00
4,00
2,00
0,00
When the engine speed exceeds 12.200 r.p.m. the torque drops and in consequence the
acceleration potential, therefore you should shift from 1
Note:
If the r.p.m. range from 9.200 to 12.200 r.p.m. is not sufficient due to a particular track shape
(extremely long straight) the maximum engine speed of 13.600 r.p.m. should be aimed for.
Note:
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It is not possible to change the 1
st
gear and 14/79 for 2
großes
Beschleunigungspotential
high acceleration potential
The maximum speed is limited at 13.800 r.p.m. by an electronic r.p.m. limiter.
A basic requirement for the full use of the speed range between 12.200 to 13.600
r.p.m. is optimized carburetor jetting (see chapter Carburetor Adjustment).
ROTAX KART RM1
manuals search engine
Operator`s Manual RM1
st nd
and 2 gear individually.
nd
gear).
BESCHLEUNIGUNGSPOTENTIAL
ACCELERATION POTENTIAL
Motordrehzahl [1/min.], engine revolutions [rpm]
st nd
into 2
Kurve des Fahrwiderstandes
graph of driving resistance
gear at 12.200 r.p.m.
Ausgabe/Edition 01/2006