Dnepr MT10-36 - Motorcycle Systems Explained; Engine Design and Lubrication

gine, as a result of which the motorcycle is slow in gaining speed;
shrill metallic knocks in the ·Cr• ank gear.
When listening to the engine, try to distinguish the knocks cau-
sed by overheating from those caused by the advance ignition set-
ting. ln case the advanced ig.nition is set, knocks are produced si-
multaneously in the both cylinde rs. The knocks caused by the engi-
ne over heating are first heard in the left-hand cylinder. This is at-
tributed bo the f, act that the temperature of the left-hand cylinder
(when operating the motorcycle with a sidecar) is always 20 to
30 oc above the temperature of the right-hand cylinder. The nor-
mal temperature of the crankcase oil must not be higher than
90 °C. A lengthy ride with the oil temperature exceeding 90 oc is
inadmissible.
It must be remembered t.hat a long-time travel with the engine
overheated may lead to a breakdown or accident.
To avoid
the overheating , the driver should run the motorcycle
over those parts of the road that are most favourable for riding and,
therefore, excluding the possibility of engine overloading. In order
to cool an overheated engine, sto ·p the motorcycle, switch out the
engi ne and allow it to cool down.
Avoid
using water for cooli ng purposes, as this may cause da-
mage to the cylinders or their heads.
To stop an overheated engi ne, reduce ~he engine s peed to a mi-
nimum and, without switch' ing off the ignition, fully close the choke
of the air corrector. The engine must stop wiJ!: hout knocks and back
·impacts. Following that, switch off the ignition.
It is not advisable to stop an overheated engine by switchi ng off
the ignition, since the engine usually co ntinu es running with the
ignition switched off, owing to f! he fuel mixture being ignited from
the high temperature surfa ·ces of the spark plugs, valves and cylin-
der heads. Besides, stopping lhe engine in this way may cause back
impacts and damage to the compo nents of the crank gear.
Operation of the engine at a slow speed under overload condi-
tions, (errati c operation of the engine) is harmful to the engine it-
self
an d to the motorcycle tr . ansmission.
The overheating is equally detrimental to bo rt: h the engine and th e
transmiss ion units. The temperature of oil in the gear box and the
main dr ·ive casing must not oxceed 85 °C.
In service, take care to keep water out of the petrol tank, crank -
case, gear box, and main drive casing. Always keep the motorcycle
units clean, especially this requi rement applies to the electrical equip-
ment devices and cooling fins of the heads and cylinders of the
engine .
When parking the motor cycle, close the petrol cock. P articula r
attention should be given to the tyre condition. The tyre pressure
must be strictly maintained within the limits specified in the rele -
vant instructions. If the tyre pressure has increased due to their hea-
2.8004