TECHNICAL INFORMATION
Conservation for engine power,
RS125R / RS250R
Measurement
of secondary
volume |
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The HRC
products are
manufactured
under severe
quality
control.
Because of
product
tolerance,
however,
certain
combination
may cause
secondary
compression
to be
slightly out
of the
standard
settings.
Pistons,
rings and
cylinders
should be
smeared with
grease to
avoid
compression
leaks.
Cylinder
heads should
be assembled
by removing
grease
around the
top with the
piston
raised at
the top dead
center. Top
gages should
be used to
check the
top dead
center. With
the cylinder
head laid
horizontally,
measurement
solution
(gasoline to
engine oil:
5 to 1) is
poured into
the plug
seating
surface
using a 50cc
burette
(injectors
with
accurate
scales are
acceptable)
to measure
the volume.
(Difference
of 0.1mm in
gasket
thickness
causes a
change of
0.2cc in
volume)
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RS125R |
Standard11.6cc |
Volume
as
assembled |
RS250R |
Standard12.1cc |
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*Note that
changes to
secondary
volume will
result in
altered
settings.
*Cylinder
gaskets
should be
replaced
every time.
If they are
reused
repeatedly,
gaskets will
become thin
by heat or
compression,
causing
changed
secondary
volume.
The 2001
year model
RS125R
should be
controlled
in cylinder
head alone
with regard
to secondary
volume since
the volume
cannot be
measured
when
installed in
vehicle.
(2001 year
head volume
of 10.9cc) |
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Ignition
timing
measurement
(from 2002
year model
RS250R) |
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For the
RS250R, top
gauge and
timing light
will be used
to check
ignition
timing. This
is not
applicable
to the
RS125.
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'99-'01 |
-'98 |
Ignition
timing |
25°±1°/6000rpm |
24°±1°/6000rpm |
20°±1°/10000rpm |
19°±1°/10000rpm |
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For 1998
year and
earlier
model with
power jet
carburetors
fitted, 1999
to 2001 year
ignition
timing
should be
used.
*Checking at
10000 rpm
will be
rather
difficult,
so
measurement
at 6000 rpm
only is
acceptable. |
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Drive
chain |
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Extended
period of
use of
chains would
cause
significantly
degraded
traction
transmission
efficiency,
resulting in
output power
drop of 2 to
3 PS.
Earlier
change of
chains is
recommended.
New chains
with initial
elongation
removed are
the best for
race use. |
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Chamber |
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Chambers
play an
important
role in
determining
the 2-stroke
engine power
characteristics.
Dented
chambers,
and carbon
or pitch
present
inside
chambers
(which is
considered
to be equal
to changes
in chamber
shapes) will
disturb
exhaust
pulsating
flow,
resulting in
significant
power loss. |
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Coolant
temperature
control |
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Coolant
temperature
control by
covering
radiators
with gum
tapes, etc.
should be
done so as
to give
coolant
temperatures
of 55°C
although
such control
cannot be
done in
summer where
the radiator
is fully
uncovered. |
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1) |
Constant
coolant
temperature
should
always
be
kept
during
carburetor
setting.
(Changes
of
five
(5)
degrees
or
more
in
coolant
temperature
will
cause
wrong
setting) |
2) |
Note
that
lower
engine
speeds
during
running
in
would
tend
to
lower
coolant
temperatures.
Coolant
temperatures
may
drop
drastically
at
cold
ambient
temperatures
in
winter,
causing
a
risk
of
cold
piston
seizures. |
3) |
For
races,
coolant
temperatures
should
be
set
to 2
to 3
degrees
lower
than
the
standard
taking
into
consideration
congested
traffic
on
circuit
courses. |
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Notes on
machine with
RAM-pressure
system |
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Fuel hoses,
when bent on
some
occasions,
may cause
fuel supply
loss. In
particular,
RAM-pressure
equipped
vehicles
contain
extended
fuel hoses,
causing fuel
hoses to be
bent when
exposed to
running
gravity
which will
result in
signs of
fuel supply
loss.
(RS125R
equipped
with
RAM-pressure)
Tubes in the
RAM-pressure
system
should not
contain
accumulation
of fuel,
which may
impede air
flow,
resulting in
degraded
performance.
Each tube
should have
an inner
diameter of
at least 5mm
or more. Too
thin tubes
will not
supply
required
amount of
air to the
tank when
the throttle
is fully
opened,
causing fuel
supply loss
at 5th and
6th speeds.
Of course,
bent hoses
should be
avoided.
In some
occasions,
clogged
one-way
section of
the strainer
may obstruct
fuel flow in
fuel lines.
Periodic
checking or
cleaning
should be
done. |
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Redline
Powersports provides the above information as a courtesy; it is the
reader's responsibility to confirm the accuracy and applicability of
all information before performing any of the discussed adjustments,
modifications, procedures, etc; furthermore, the implementation of
any of the discussed adjustments, modifications, procedures, etc is
done at the sole risk of the reader. Redline
Powersports does NOT warranty or guarantee in any way the
information discussed in it's "Technical Information" pages or
elsewhere. Redline Powersports disclaims all responsibility
for consequential and incidental damages or any other loss arising
from the use of ANY information provided by Redline Powersports
and/or it’s vendors, suppliers, contractors, etc. irrespective of
how caused.
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