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R 95 Manual - English
R 95 Manual - English
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9. Service tips
Experiences from the previous engine model,
Raket 85, have taught us that a Raket engine
should normally not require any comprehen
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sive levels of service during a racing season,
since we believe that a R 95 engine will be
used no more than 50 times per season. We
do not believe that it should be necessary
to change bearings, sealing rings and piston
rings several times during a season, such as is
required with more extreme kart engines. It
is of course up to every driver and mechanic
to make their own decisions about what they
think is necessary or best.
The following simple service routines can
however be said to fall into the category of
normal maintenance work:
1. Lubricating the clutch parts.
We recommend that you lubricate the bear
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ing of the clutch drum. The clutch it self shall
be clean and not lubricated.
2. Silencer
As we mentioned previously, it is possible
to drill out the rivets at the back edge of the
silencer.
When you have done this you can remove the
end of the barrel and thus even the damping
material that is lying wrapped around the
barrel. Assuming that the carburettor is setup
normally and correctly it should not be neces
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sary to change the damping material during
a season. However we would recommend a
change prior to the start of each new season.
3. Servicing the carburettor
The only aspect of your R 95 engine that
requires regular service is the carburettor.
A diaphragm carburettor is a quite amazing
component that is capable of operating in
chainsaws, cutters and other testing applica
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tions whilst working problem-free for several
years at a time. As long as you are careful
to only refuel using well-filtered fuel, and
always drive with the inlet silencer attached,
then you should also be able to get through
a season without needing to disassemble the
carburettor for cleaning and control. On the
other hand you must possess the ability to
clean and setup your carburettor. To that end
there now follows a short tutorial in carburet
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tor service.
The carburettor is a Tillotson 319 A. If we
follow the passage of the petrol through the
carburettor we will be able to quickly describe
the carburettor’s function.
The carburettor has two caps, one made of
metal while the other is mould cast. Under
the moulded cap lie a rubber diaphragm and
a gasket. There is a small chamber on each
side.
One of these chambers is connected to the
engine’s crankcase via a channel. When the
pressure in the crankcase changes the pump
diaphragm in the carburettor will begin to
move. On the other side of the diaphragm
there is fuel in the other chamber. When
the diaphragm moves the fuel is pumped in
and out of the chamber. Two small lip valves
that are cut-out in the same piece of rubber
ensure that suction from the tank occurs and
that the fuel is pumped further towards the
carburettor’s inlet valve. The pump should
sustain a pressure of approx.0.5 kp/cm2.
It is quite simple to check if the pump is work
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ing correctly. Take off the spark plug so that
it will be easier to move around the engine.
Ensure that the fuel line is correctly attached
and that the carburettor is sitting correctly on
the engine. All gaskets should be OK. Ensure
that the hose running from the crankcase
to the carburettor is in place. Press care
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fully (we emphasise – CAREFULLY) down on
the master diaphragm which you can reach
through the small hole on the die-cut cover
of the carburettor. When you press down on
the diaphragm the inlet valve opens. Turn the
engine around and check to see if there is any
fuel coming from the tank.
If no fuel is coming then you should firstly
loosen the fuel line from the tank and blow
into the hose. You should still be pressing
down on the carburettor diaphragm. You
should feel that it is possible to blow air
through the carburettor. If you are not able
to blow air through the carburettor then you
should take off the moulded cap, because
there is obviously something wrong. Firstly
check the small fuel strainer (this has article
number 3043 in the spare parts list). It may
be clogged.
After that it is time to focus on the pump dia
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phragm itself. It could be worn out, but that is
actually difficult to determine with the naked
eye; however if it has been used for a while
then you should change it! Remember that
one should always change the gasket when
one changes the diaphragm.
The rule is: The diaphragm should be facing
the carburettor casing – otherwise the lip
valves will not seal!
Now the pump should be working OK, which
you can check by using the same method as
we have previously described. If you still –
despite everything – are not able to receive
fuel then the needle valve must be stuck and
in that case there is nothing else to do than to
continue. The pump pushes the fuel forward
towards the needle valve, but it cannot open
it through its own force. The needle valve is
held closed by a spring that operates over a
lever. The master diaphragm works against
the lever, which we know from the small rivet
in the middle of the diaphragm. One side of
the diaphragm is in contact with the carbu
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Summary of Contents for R 95
Page 1: ...Owners Manual ENGLISH ...
