It is of vital importance, before attempting to
operate your engine, to read the general
'SAFETY INSTRUCTIONS AND WARNINGS'
section on pages 2-5 of this booklet and to strictly
adhere to the advice contained therein.
Also, please study the entire contents of this
instruction manual, so as to familiarize yourself
with the controls and other features of the
engine.
Keep these instructions in a safe place so that
you may readily refer to them whenever
necessary.
It is suggested that any instructions supplied
with the vehicle, radio control equipment, etc.,
are accessible for checking at the same time.
CONTENTS
SAFETY INSTRUCTIONS AND
WARNINGS ABOUT YOUR O.S. ENGINE
INTRODUCTION, BASIC ENGINE PARTS
INSTALLATION OF THE ENNGINE
INSTALLATION OF THE CARBURETOR
AIR CLEANER TYPE201
NOTES CONCERNING THE RECOIL STARTER
GLOWPLUG
TOOLS, ACCESSORIES, etc.
CARBURETOR CONTROLS,
PRESSURIZED FUEL SYSTEM
STARTING THE ENGINE &
RUNNING-IN('Breaking-in)
2-5
7-8
9-12
12
13
13-14
15
15-18
IF THE ENGINE FAILS TO START
FINAL ADJUSTMENT
6
CARBURETOR CLEANLINESS
8
BEFORE STARTING THE ENGINE
CARE AND MAINTENANCE
GUARANTEE
O.S. GENUINE PARTS & ACCESSORIES
ENGINE EXPLODED VIEW
& ENGINE PARTS LIST
CARBURETOR EXPLODED VIEW
& PARTS LIST
THREE VIEW DRAWING
1
18
18-19
20
21
21-22
22
23
24-27
28-29
30
SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE
Remember that your engine is not a "toy", but a highly efficient internalcombustion machine whose power is capable of harming you, or others, if it is
misused.
As owner, you, alone, are responsible for the safe operation of your engine, so act
with discretion and care at all times.
If at some future date, your O.S. engine is acquired by another person, we would
respectfully request that these instructions are also passed on to its new owner.
The advice which follows applies basically to ALL MODEL ENGINES and is
grouped under two headings according to the degree of damage or danger
which might arise through misuse or neglect.
WARNINGS
!
These cover events which
might involve serious (in
extreme circumstances, even
fatal) injury.
!
•
Model engine fuel is poisonous. Do not allow it to
come into contact with the
eyes or mouth. Always store
it in a clearly marked container and out of the reach
of children.
Model engine fuel is also
•
highly flammable. Keep it
away from open flame,
excessive heat, sources of
sparks, or anything else
which might ignite it. Do not
smoke or allow anyone else
to smoke, near to it.
These cover the many other
possibilities, generally less obvious
sources of danger, but which, under
certain circumstances, may also
cause damage or injury.
2
WARNINGS
•
Never operate your engine in an enclosed space. Model engines, like
automobile engines, exhaust deadly
carbon-monoxide. Run your engine
only in an open area.
Model engines generate
•
considerable heat. Do not
touch any part of your
engine until it has cooled.
Contact with the muffler
(silencer), cylinder head
or exhaust header pipe, in
particular, may result in a
serious burn.
!
NOTES
3
!
This engine is intended for model cars.
•
Do not attempt to use it for any other
purpose.
Mount the engine in your model
•
securely, following the manufacturers'
recommendations, using appropriate
screws and locknuts.
Fit an effective silencer (muffler).
•
Frequent close exposure to a noisy
exhaust (especially in the case of the
more powerful highspeed engines)
may eventually impair your hearing
and such noise is also likely to cause
annoyance to others over a wide area.
NOTES
•
The wearing of safety glasses is also
strongly recommended.
Take care that the glowplug clip or
•
battery leads do not come into contact
with rotating parts. Also check that the
linkage to the throttle arm is secure.
For their safety, keep all onlookers
•
(especially small children) well back
(at least 20 feet or 6 meters) when
preparing your model for running.
4
!
•
To stop the engine, fully retard the
throttle stick and trim lever on the
trans-mitter, or, in an emergency, cut
off the fuel supply by pinching the fuel
delivery tube from the tank.
Do not attempt to disassemble the
•
recoil starter.
If you do so, the very strong spring
inside will be suddenly ejected. This
can be very dangerous.
Do not extend the starter cord more
•
than 45cm (18"). Do not abruptly
release the operating handle. Allow
the cord to rewind smoothly while
still holding the handle.
NOTES
•
Pull the operating handle straight out
when starting the engine, so that the
cord does not rub against the vehicle
body or engine. This will help prevent
the cord from being damaged by
abrasion or engine heat.
•
Warning! Immediately after a glowplugignition engine has been run and is still
warm, conditions sometimes exist
whereby it is just possible for the engine
to abruptly restart if it is rotated over
compression WITHOUT the glowplug
battery being reconnected.
5
The MAX-21RG Series has been developed for
1/8 scale off-road 'buggy' and scale cars.It
provides a combination of performance and
value that brings it within the reach of a larger
group of R/C model vehicle enthusiasts, from
newcomers to experienced competitors. All
major parts of the MAX-21RG have been
redesigned. Its potential is very close to that of
the top-ranking MAX-21RZ motors, but it
remains easy to operate and is considerably
less expensive. The MAX-21RG has a
conventional crankshaft, while the MAX21RG(P) employs a special crankshaft with
integral pilot shaft. The MAX-21RG-X and
MAX-21RG(P)-X have the addition of a built-in
O.S. recoil starting system. The starter unit
eliminates the need for a separate electric
starter and battery.
NOTE: With this engine, the piston will feel tight at
the top of its stroke when the engine is cold. This
is normal. The piston and cylinder are designed to
achieve a perfect running clearance when they
reach their normal running temperatures.
BASIC ENGINE PARTS
Carburetor
Beam Mount
Crankcase
Crankshaft
6
Heatsink Head
Starter Handle
Recoil Starter
Assembly No.5
MAX-
21RG-X
INSTALLING
THE GLOWPLUG
Install the washer on the
glowplug and insert carefully into
cylinder-head, making sure that it
is not cross-threaded before
tightening firmly.
Glow plug
Washer
ENGINE INSTALLATION
Make sure that the vehicle's engine mounting surfaces
are level and in the same plane. Poor installation may
cause distortion of the crankcase, bearings, etc.,
resulting in erratic running and loss of performance.
The recommended screws for securing the engine are
3mm or 4-40 steel Allen hexagon socket type.
If existing holes in the engine mount do not align
perfectly with engine mounting lugs, enlarge them
slightly with a needle-file so that screws align with the
mounting holes.
Chassis
Chamfer inside edges of bearers.
Do not allow bottom
of crankcase to touch
chassis.
7
Avoid forcing the screws. Secure with locknuts. If the
bottom of the recoil starter housing touches the car
chassis, install the engine mount spacers (supplied)
between the engine's mounting lugs and the engine
mount. Use the M3x15 screws provided. With some
vehicles, it may be necessary to make minor trimming
modifications to chassis or body when fitting the engine.
NOTE:
Where spacers are supplied joined in pairs (see
sketch) separate them as shown.
Either face may be placed downwards.
INSTALLATION OF THE CARBURETOR
As delivered, the engine has its carburetor lightly
fitted into its intake boss. Secure it as follows.
Loosen the retainer screw, rotate the carburetor to
1.
its correct position and make sure that it is pressed
well down into the intake boss, compressing the
rubber gasket, before retightening screw.
Rotate the retainer screw gently until it stops, then
2.
tighten a further 90-120˚.
Do not overtighten the screw as this will damage
the carburetor body.
Separate
←→
Rotate the retainer nut
gently until it stops.
Tighten a further 90-120˚
Mount Spacer
Engine Mount
Engine Mount
Spacer
8
AIR CLEANER TYPE 201
This is a heavy-duty wet type air cleaner that has been developed specifically for 3.5cc 'off-road' model car
engines. It contains a specially impregnated filter element which more positively prevents highly damaging dust and
dirt from being drawn through the carburettor, yet allows engine performance to be maintained for longer periods
between element renewals. It is more compact than the standard O.S. HD Air Cleaner and this makes it easier to
install within a car body. This air cleaner is also supplied with a newly designed intake elbow that provides more
secure attachment to the caburetor.
Assembly Screw
End Plate
Filter Element
Center Screen
Element Base
9
Intake Elbow
Strap
Center T ube
Strap
ASSEMBLY
Slide the element base over the center tube (See
1.
Fig.1) and press down.
If it is tight at the bottom, apply one or two drops of
・
fuel at the point marked in Fig.2
Press down near to the center (not the outside) to
・
avoid risk of breaking the element base.
Apply pressure until the element base fits firmly
・
against the collar of the center tube (Fig.3).
Element Base
Center T ube
Fig.1
2. Installing the element.
The element is already impregnated with a special
・
filter oil. As this oil is very sticky, take care, when
handling it, to prevent dust or dirt adhering to the
element, especially to its inner surface before
insertion of the center screen.
Press at center.
Apply one or two
drops of fuel.
Fig.2
Press down
firmly.
Fig.3
If your fingers become contaminated, wash them with
soap and water.
NOTE: During storage, the oil may have become
unevenly dispersed through the element. This will
be indicated if the blue color of the element
material appears patchy.
In this case, place the element in a small plastic
bag and gently rub the element between finger
and thumb to redistribute the oil.
Now insert the cylindrical center screen into the
・
element, followed by the center tube.
Do not, at anytime, omit the screen: it is essential for
releasing air to the engine evenly.
Fit the end plate, washer and retaining screw,
・
making sure that the element fits correctly between
the end plate and base.
Element
misaligned
10
INSTALLATION
Apply instant setting
1.
glue to the joint between the air cleaner
and the intake elbow
and secure with strap
supplied.
Fit the other end of
2.
Apply instant fixing glue.
Washer
Assembly
Do not apply
glue to
carburettor
Screw
Strut
the elbow over the carburettor intake and secure with
strap supplied. Do not use glue at this point.
It is advisable to brace the outer end of the air
3.
cleaner to the car chassis with a piano wire strut.
This will restrain the cleaner in the event of the
vehicle overturning or being involved in a collision.
REPLACEMENT OF ELEMENT
Under very dusty conditions, it is advisable to
1.
replace the filter element after each hour of running
time.
2.
Under less severe conditions, however, it may be
possible to operate for longer periods. The rate at
which the elements become unusable may be
determined as follows.
After one hour of running time, remove the element
・
but, before discarding it, check the penetration of
foreign matter by cutting through the wall of the
element. If dirt has
penetrated 1/3rd or more from the
outer surface, each element must always be
replaced within one hour, when the vehicle is run
under similar conditions. If, on the other hand, the
element is much less deeply soiled, the engine may
be run a little longer before another new element is
installed, but remember to check the condition of the
discarded element, as before. If the old element is
examined in this way
every time a new element
is fitted, one can more
closely estimate the safe
life of the element under
known running conditions.
・
Remember that the condition of the filter element will
depend on weather, as well as track conditions. If, for
example, the element surface is still visible and
remains moist, further running is permissible.
If, however, the surface is no longer visible, or if dust
・
adhering to the surface has become dry, it is time to
replace the element.
11
1
3
FURTHER PRECAUTIONS
When removing the air cleaner, check the inside of the
center tube and carburetor venturi. If any dirt is detected,
this indicates that the filter element was incorrectly
installed or should have been replaced earlier.In this
event, it is vitally important to wash out the inside of the
engine thoroughly, with alcohol or fuel,before it is used
again, otherwise rapid wear of the piston,
cylinder,bearings, connecting-rod, etc., will occur.
Obviously, it will be necessary to carry out the same
procedure with the air cleaner and to replace the filter
element.
NOTE: Be careful not to splash alcohol or fuel
over the filter element, or the filter oil will be
diluted, and the filter capacity lowered.
NOTES CONCERNING THE RECOIL STARTER
REMINDER!
Do not attempt to disassemble the recoil starter.
◆
If you do so, the very strong spring inside will be
suddenly ejected. This can be very dangerous.
Do not extend the starter cord more than
◆
45cm(18"). Do not abruptly release the operating
handle. Allow the cord to rewind smoothly while
still holding the handle.
Pull the operating handle straight out when
◆
starting the engine, so that the cord does not
rub against the vehicle body or engine.
This will help prevent the cord from being
◆
damaged by abrasion or engine heat.
Try to avoid spilling fuel over the starter unit and
◆
its cord. Some fuels have a detrimental effect on
these parts.
The starter prevents the engine from being ro-
◆
tated in the wrong direction.The unit will be
damaged if you attempt to force the flywheel in
the opposite direction (i.e. clockwise when
viewed from the crankshaft end).
NOTE:
Because, in the interests of personal safety,
dismantling of the starter mechanism is strongly
discouraged, the Recoil Starter is available for
replacement only as a pre-assembled unit.
However, some related parts, such as Starting
Shaft and Rear Adaptor, are obtainable separately.
(See Parts List.)
12
GLOWPLUG
Since the glowplug and fuel combination used may
have a marked effect on performance and reliability, it
would be worthwhile to experiment with different plug
types. An O .S. N o.8 gl owplug is supplied with the
engine. Other Recommended O.S. plugs are A3 and
A5. Carefully install plug finger-tight, before final tightening with the correct size plug wrench.
The role of the glowplug
With a glowplug engine, ignition is initiated by the
application of a 1.5-volt power source. When the
battery is disconnected, the heat retained within the
combustion chamber remains sufficient to keep the
plug filament glowing, thereby continuing to keep the
engine running. Ignition timing is 'automatic' : under
reduced load, allowing higher rpm, the plug becomes
hotter and, appropriately, fires the fuel/air charge
earlier; conversely, at reduced rpm, the plug become
cooler and ignition is retarded.
Glowplug life
Particularly in the case of very high performance
engines,
glowplugs must be regarded as expendable
items. However, plug life can be extended and engine
performance maintained by careful use, i.e.:
Install a plug suitable for the engine.
•
Use fuel containing a moderate percentage of
•
nitromethane unless more is essential for racing
events.
Do not run the engine too lean and do not leave the
•
battery connected while adjusting the needle.
When to replace the glowplug
Apart from when actually burned out, a plug may
need to be replaced because it no longer delivers its
best performance, such as when:
Filament surface has roughened and turned white.
•
Filament coil has become distorted.
•
Foreign matter has adhered to filament or plug
•
body has corroded.
Engine tends to cut out when idling.
•
Starting qualities deteriorate.
TOOLS, ACCESSORIES, etc.
The following items are necessary for operating the
engine.
FUEL
Generally, it is suggested that the user selects a fuel that
is commercially available for model two-stroke eengines
13
and contains between 10% and 30% nitromethane. As
a starting point, we recommend a fuel containing 10%
nitromethane, changing to a fuel containing more nitro
if necessary. When the brand of fuel is changed, or the
nitro content increased, it is advisable to repeat the
running-in procedure referred to in the RUNNING-IN
paragraphs. For consistent performance and long
engine life, it is essential to use a good quality fuel
containing NOT LESS THAN 18% lubricant. Please
note that with high-nitro fuels, although power may be
increased for competition purposes, glowplug elements
do not last so long and engine life will be shortened.
Reminder!
Model engine fuel is poisonous. Do not
allow it to come into contact with the eyes or
!
mouth. Always store it in a clearly marked
container and out of the reach of children.
Model engine fuel is also highly flammable.
Keep it away from open flame, excessive heat,
!
sources of sparks, or anything else which
might ignite it.
GLOWPLUG BATTERY
The power source for heating the glowplug ma y be either
a large heavy-duty 1.5V olt dry cell, or a 2-Volt rechargeab le
lead-acid cell with extended leads (or a resistance) to
reduce the applied voltage to approximately 1.5-V.
BATTERY LEADS
These are used to conduct current from the battery to
the glowplug. For convenience,special leads with a
suitable clip to fit the glowplug terminal, are
commercially available.
LONG SOCKET WRENCH
Recommended for easy removal and
replacement of the angled and recessed
glowplug, the O.S.Long Socket Wrench
incorporates a special grip.
FUEL BOTTLE OR PUMP
For filling the fuel tank, a simple, polyethylene
"squeeze" bottle, with a suitable spout, is required.
ELECTRIC STARTER AND STARTER BATTERY
Use an electric starter with 12-volt
battery for starting the MAX21RG/RG(P).
SILICONE FUEL LINE
Heatproof silicone fuel line of approx. 5mm
o.d. and 2mm bore is required for the piping
between the fuel tank and engine.
14
CARBURETOR CONTROLS
Three adjustable controls are provided on this
carburetor.
・
The Needle-Valve:
For adjusting the mixture strength when the throttle
is fully open.
・
The Mixture Control Screw:
For adjusting the mixture strength at part-throttle
and idling speeds, to obtain steady idling and
smooth acceleration to mid speeds.
The Throttle Stop Screw:
・
For setting the minimum idling speed:
Ball Link
Slide Valve
Guide Screw
NOTE: Readjustment may be necessary,
occasionally to allow for changes in fuel formula,
gear ratio or clutch engagement point.
Needle Valve
Mixture Control Valve
Assembly Screw
Throttle Stop Screw
PRESSURIZED FUEL SYSTEM
The somewhat violent changes of vehicle attitude
•
that occur in off-road running, combined with the
fact that, in buggy type cars, the fuel tank is often
located some way from the carburetor, means that
fuel 'head' at the carburetor can vary a and upset
running.Therefore,it is recommended that a muffler
pressurized fuel feed system be used.
Never run your vehicle without installing the air
•
cleaner. Dust and dirt that may otherwise be drawn
into the engine will rapidly shorten its life.
Connect suitable length of
Fuel Tank
15
Silicone fuel line between fuel
tank and silencer.
Silicone fuel line
Silencer
STARTING THE ENGINE & RUNNING-IN ('Breaking-in')
For long life and high performance, every engine needs
to be properly 'run-in' or 'broken-in'. The running-in
procedure for this engine can be carried out with the
engine installed in the model. Be sure to use a muffler
pressurized fuel system. The running-in procedure is
as follows.
Use the same fuel as is to be employed for all initial
•
running and containing NOT LESS THAN 18%
lubricant.
Temporarily remove the glowplug to check that it
•
glows bright red when energized.
Re-check the needle-valve and
•
throttle settings. Turn the needlevalve clockwise slowly and gently
until it stops. This is the fully closed
position.Do not use force to turn the
needle-valve beyond this point.
Open the Needle-Valve 3 turns
•
from the fully closed position.
Switch on the transmitter and receiver
•
and set the throttle very slightly
opened from the idling position.
Close
Open
0.3〜0.5mm
Needle Valve
DO NOT energize glowplug,
•
but apply electric starter to
draw fuel to carburetor.
Now connect glowplug battery
•
lead to heat the plug filament
and start the engine.
In case of the 21RG-X and
■
21RG(P)-X
Push the choke button on
•
the fuel tank several times to
deliver the fuel to the
carburetor. (Do not overprime or the recoil starter
cannot be pulled.)
Pull the starter handle
•
briskly straight out several
times to start the engine.
16
Glowplug
Starting battery
Front
Rear
Starter Handle
Rotating
Direction
Remember!
It is vitally important to set the
throttle at the correct position
before attempting to start the
engine.If the engine is
allowed to run with the
throttle too far open under
"no load" conditions, it will
rapidly overheat and may be seriously damaged.
When the engine starts, first allow it to operate in short
•
runs on its very rich starting settings, with the glowplug
battery still connected and with its driving wheels clear
of the ground.The rich mixture will, under these
conditions, provide adequate lubrication and cooling,
indicated by profuse smoke from the exhaust.
Next, disconnect the glowplug battery and try
•
running the car on the track. If the engine stalls, open
the throttle fractionally, but try to keep the engine
running as rich as possible: if it stops because of
being excessively over-rich, close the Needle-Valve
30˚ and try again.
Run the car on the track until one tank of fuel has been
•
consumed, then close the Needle-Valve 30˚ and run
the car for another full tank of fuel.
Repeat this procedure until 5 more tanks of fuel have
been consumed, during which time the throttle may
be opened for brief bursts of increased power. If the
engine stops at medium speeds, close the Mixture
Screw 30˚.
Needle
To stop the engine, close the throttle to idling speed,
•
then shut it off completely with the trim lever on the
transmitter. To cut off the fuel supply, pinch the fuel
delivery tube to the carburetor.
Remember!
If the engine should need to be disassembled (e.g.
for cleaning or minor parts replacement) it is
advisable to return the Needle-Valve to the original
rich, starting setting and check whether further
running-in time is required before the car is raced
again. In the event of any major working parts (e,g,
piston/cylinder liner assembly) being replaced, the
complete running-in should be repeated.
The position of the needle-valve
30º
when starting the engine.
30º
Close the needle-valve approx.
30º
30˚ after running the vehicle for
one full tank of fuel.
Repeat this procedure several
times.
17
IF THE ENGINE FAILS TO START
Check the following:
Glowplug battery discharged or glowplug defunct.
•
Fuel not reaching carburetor.
•
Engine flooded. Do not over-prime. (This could also
•
cause hydraulic lock and damage the engine on
application of the electric starter.)
Remove glowplug, close needle-valve and apply
starter to pump out surplus fuel. At this time cover
the plug hole with a rag so that fuel will not splash
into your eyes or mouth.
In case of the 21RG-X and
21RG(P)-X
FINAL ADJUSTMENT
Run the vehicle (with throttle fully open) over the
•
longest available straight course, in order to observe
the model's speed. Next return the car to the starting
point, close the Needle-Valve 30˚ and repeat the
run, taking note of the improvement in performance.
Continue with further runs, gradually reducing the
Needle-Valve setting and aiming to achieve the
highest straight-line speed. Remember, however,
that, if the Needle-Valve is shut down too far, the
engine will overheat and, accompanied by visibly
diminished exhaust smoke, the model will lose
speed. At this point, throttle down immediately, stop
the vehicle and reopen the Needle-Valve 30˚.
Having established the optimum Needle-Valve
•
setting, check the Mixture Control Valve setting as
follows.
With the engine running, close the throttle and allow
•
it to idle for about five seconds, then reopen the
throttle fully. If, at this point, the engine puffs out an
excessive amount of smoke and the vehicle does
not accelerate smoothly and rapidly, it is probable
that the idling mixture is too rich.
18
In this case, turn the Mixture Control Valve
•
clockwise 30˚. If, on the other hand, the engine
tends to speed up momentarily and then cut out
abruptly when the throttle is opened,the idling
mixture is too lean. Correct this by turning the
Mixture Control Valve counter-clockwise 30~45˚.
NOTE:
Mixture Control Valve adjustment should be made
in steps of not more than 30~45˚, carefully
checking the effect,on throttle response, of each
small adjustment.
Carry out adjustments patiently, under actual
•
running conditions, until the engine responds
quickly and positively to the throttle control.
Warning!
Mixture adjustments (whether via the Mixture
Control Valve, or the Needle-Valve) cannot be
made accurately under 'no-load' conditions,
which, in any case, are not advised, since such
operation carries the risk of seriously damaging
the engine through over-revving and overheating.
With the optimum mixture control position, light
•
smoke is visible during high speed running,and the
engine revolutions increase smoothly during
acceleration. Remember that, if the engine is
operated with the fuel/air mixture slightly too lean, it
will overheat and run unevenly. As with all engines,
it is advisable to set both needle-valve and mixture
control screw very slightly on the rich side of the best
rpm setting, as a safety measure.
If the engine runs too fast with the throttle closed,
•
the throttle stop screw should be turned counterclockwise to allow the throttle opening to be
reduced.
Finally, beyond the nominal break-in period, a slight
•
readjustment toward a leaner needle setting may be
required to maintain performance.
19
CARBURETOR CLEANLINESS
The correct functioning of the carburetor depends on
its small fuel orifices remaining clear.
(See Care and Maintenance section on Page21.)
■
BALL LINK AND SLIDE VALVE EXTENSION
When readjusting the position of the Ball Link, always
apply a 6mm spanner (wrench) to the flats in the
Slide Valve Extension, before attempting to loosen or
tighten the ball link retaining screw. Carefully ease
back the Dust Cover bellows to allow access to the
flats. If it should become necessary (e.g. for cleaning)
to disassemble the throttle parts, first unscrew the
Slide Valve guide screw and withdraw the complete
sub-assembly from the carburettor body. Use the
correct size (8mm) wrench when unscrewing the
Slide Valve from the Slide Valve Extension.
'Flats' for spanners
■
REALIGNMENT OF MIXTURE CONTROL VALVE
In the course of making carburetor adjustments, it is
just possible that the Mixture Control Valve may be
inadvertently screwed in or out too far and thereby
moved beyond its effective adjustment range.Its basic
position can be found by first rotating the Mixture
Control Valve until its slotted head is flush with the
carburettor body. The valve is then screwed in exactly
1 turn to re-establish its neutral position.
First rotate the Mixture Control
Valve until its slotted head is
flush with the carburetorbody.
Then screw the valve in exactly
1 turn.
This is the standard position.
Mixture Control Valve
Carburetor Body
Slide Valve
Slide Valve Extension
BEFORE STARTING THE ENGINE
Before starting the engine for the first run of the day,
1.
remove the glowplug and check the engine by
rotating the flywheel by hand. It should rotate
smoothly. Now turn the engine with an electric
starter until fuel is drawn into the carburetor. At first,
rotation may feel 'sticky' due to oily residue
remaining within the engine. The engine should
rotate freely after fresh fuel has been drawn into the
working parts.
Check the glowplug. If the plug element is distorted,
2.
off-center, or has a white appearance, engine
performance may be below par. With racing type
engines, glowplugs have to be regarded as
consumable items. Therefore, replace the plug if
necessary.
3.Re-install the glowplug and start the engine.
4.
When re-starting the engine, turn the flywheel by
hand, as before (but without removing the glowplug) to make sure that there is nothing unusual,
before energising the glowplug and applying the
starter.
20
Warning!
Do not attempt to turn the engine with the starter
if the engine is over-primed (flooded) with fuel.
To do so is likely to seriously damage the engine.
CARE AND MAINTENANCE
1.
The minute particles of foreign matter, that are
present in any fuel may, by accumulating and
partially obstructing fuel flow, cause engine
performance to become erratic and unreliable.
O.S. 'Super-Filters' (large and small) are available,
as optional extras, to deal with this problem.
One of these filters, installed the outlet tube inside
your refueling container, will prevent the entry of
foreign material into the fuel tank. It is also
recommended that a good in-line filter be installed
between the tank and carburetor.
Do not forget to clean the filters regularly to remove
2.
dirt and lint that accumulate on the filter screens.
Also, clean the carburetor itself occasionally.
At the end of each operating session, drain out any
3.
fuel that may remain in the fuel tank.
Afterwards,energize the glow-plug and try to restart
the engine, to burn off any fuel that may remain
21
inside the engine. Repeat this procedure until the
engine fails to fire. Do this while the engine is still
warm.
Then, inject some after-run oil into the engine, and
4.
rotate the engine with an electric starter for 4 to 5
seconds to distribute the oil to all the working
parts.
Note:
Do not inject after-run oil into the carburetor as
this may cause the O-rings inside the carburetor
to deteriorate. These procedures will reduce the
risks of starting difficulties or corrosion after a
period of storage.
Finally, when cleaning the exterior of the engine,
5.
use methanol or kerosene. Do not use gasoline or
any solvent that might damage the silicone fuel
tubing.
Caution:
The rear crankshaft bearing of this engine uses a
special plastic retainer. If the front housing needs
to be heated to remove or replace the bearing, do
not allow the bearing to exceed 120˚C (248˚F),
otherwise it may be damaged and rendered
unserviceable.
GUARANTEE
This engine is constructed from the very best
materials available and to the very highest
engineering standards, using the most advanced
precision machinery. However, the extremely high
stresses imposed by car racing operation under very
severe conditions, stresses which are exacerbated by
the use of powerful fuels containing very high
concentrations of nitromethane, constitute hazards
which are beyond a manufacturer's control.
Accordingly, we regret that it is not possible to extend
our usual warranty terms to this particular engine -i.e.
no guarantee is offered against material wear, or
damage resulting therefrom, in actual use.
22
RACING ENGINE PARTS
Drive Hub
■
(23908000)
Glow Plug
■
No.8
(71608001)
Super Joint Tube 21
■
(72106300)
A5
(71605100)
■
■
O.S. GENUINE PARTS & ACCESSORIES
T-2030Tuned Silencer
(72106030)
Crankshaft Clamp
1521
(71530200)
■
Long Socket Wrench
With Plug Grip
(71521000)
23
Exhaust Header Pipe For
■
21RG-X
(72103510)
Cap Screw Set
■
(10pcs. set)
M2.6x7
M2.6x15
M2.6x18
(79871020)
(79871050)
(79871055)
21RG, 21RG(P) ENGINE EXPLODED VIEW
C.M2.6x15
24
1
2
6
4
C.M2.6x18
7
8
3
5
9
13
10
4
11
C.M3x8
12
12-A
C.M2.6x7
14
21RG, 21RG(P) ENGINE PARTS LIST
No.
Code No.
1
23604010
2
23603000
3
23906000
4
23817000
5
23605000
6
15
25
7
8
9
10
11
12
12-A
13
14
15
23618001
23981700
41614000
23601000
23626100
22830000
23602000
23602010
23614000
23607000
22447005
72411000
72411020
72411050
72411010
72411040
72411030
71608001
The specifications are subject to alteration for improvement without notice.
Heatsink Head
Cylinder & Piston Assembly
Piston Pin
Piston Pin Retainer (2pcs.)
Connecting Rod
Carburetor Complete (Type 20E)
Carburetor Retainer (with screw)
Crankshaft Ball Bearing (Front)
Crankcase
Exhaust Adaptor (No.5)
Crankshaft Ball Bearing (Rear)
Crankshaft (For 21RG)
Crankshaft (For 21RG(P))
Gasket Set
Cover Plate
Screw Set
Super Air Cleaner 201 (W/two filter elements)
201 Filter Elements (4pcs.)
Element Plate Set Comprising:
Center Screen
Intake Elbow
Center Tube
Glow Plug No.8
Description
Type of screw
C...Cap Screw M...Oval Fillister-Head Screw
F...Flat Head Screw N...Round Head Screw S...Set Screw
21RG-X, 21RG(P)-X ENGINE EXPLODED VIEW
21RG-X, 21RG(P)-X ENGINE PARTS LIST
C.M2.6x15
1
7
6
4
C.M2.6x18
9
8
13
26
15
Type of screw
C...Cap Screw M...Oval Fillister-Head Screw
F...Flat Head Screw N...Round Head Screw S...Set Screw
5
2
3
4
10
C.M2.6x7
14
No.
Code No.
1
23604010
2
23603000
3
23906000
4
23817000
5
23605000
6
23618001
7
12
27
M.+M2.6x7
11
11-A
8
9
10
11
11-A
12
13
14
15
16
16-1
16-2
23981700
41614000
23601000
22830000
23602030
23602020
23614000
23602050
23601800
22447005
73003000
73003100
73003200
72404110
72411000
72411020
16-2
16-1
16
72411050
72411010
72411040
72411030
71608001
The specifications are subject to alteration for improvement without notice.
Heatsink Head
Cylinder & Piston Assembly
Piston Pin
Piston Pin Retainer (2pcs.)
Connecting Rod
Carburetor Complete (Type 20E)
Carburetor Retainer (with screw)
Crankshaft Ball Bearing (Front)
Crankcase
Crankshaft Ball Bearing (Rear)
Crankshaft (For 21RG-X)
Crankshaft (For 21RG(P)-X)
Gasket Set
Starting Shaft
Rear Adaptor
Screw Set
No.5 Recoil Starter Assembly
No.5 Recoil Starter Body
No.5 Oneway Clutch
Mount Spacer
Super Air Cleaner 201 (W/two filter elements)
201 Filter Elements (4pcs.)
Element Plate Set Comprising:
Center Screen
Intake Elbow
Center Tube
Glow Plug No.8
Description
CARBURETOR EXPLODED VIEW
3-2
3-1
3
2
1-1
1-2
1
Type of screw
C...Cap Screw M...Oval Fillister-Head Screw
F...Flat Head Screw N...Round Head Screw S...Set Screw
3-3
3-4
4
5
6
11
7
8
9
10
C.M2.6x7
28
CARBURETOR PARTS LIST
No.
Code No.
23818180
1
46066319
1-1
22781800
1-2
23818500
2
23618190
3
23618197
3-1
46066319
3-2
23618194
3-3
23818176
3-4
23618102
4
45581820
5
23818251
6
23818310
7
23818220
8
22884220
9
23818400
10
29015019
11
The specifications are subject to alteration for improvement without notice.
Mixture Control Valve Assembly
Description
"O" Ring(L) (2pcs.)
"O" Ring(S) (2pcs.)
Throttle Stop Screw
Needle Valve Assembly
Needle Assembly
"O" Ring
Needle Holder Assembly
Universal Nipple No.9
Carburetor Body
Slide Valve Guide Screw
Slide Valve
Metering Needle Assembly
Slide Valve Extension
Dust Cover
Ball Link No.1
Carburetor Rubber Gasket
29
THREE VIEW DRA WING
Displacement
Bore
Stroke
Practical R.P.M.
Power output
Weight
SPECIFICATIONS
3.46 cc / 0.211 cu. in
16.6 mm / 0.654 in
16.0 mm / 0.630 in
3,000-35,000 r.p.m.
1.9 ps / 30,000 r.p.m.
325g / 11.47 oz.(RG,RG(P))
397.5g / 14.03 oz.(RG-X,RG(P)-X)
29.6
45
UNF1/4-28
30
44
84 (65.6)
Dimensions(mm)
33.5
21
37
10.5
4- 3.3
54
80.7
95.8
40
( ) -RG/RG(P)
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Copyright 2000 by O.S.Engines Mfg. Co., Ltd. All rights reserved. Printed in Japan.
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6-15 3-Chome Imagawa Higashisumiyoshi-ku
Osaka 546-0003, Japan
URL : http://www.os-engines.co.jp
TEL.(06) 6702-0225
FAX. (06) 6704-2722
60091020 050403
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