MAX-21VZ-B V-SpecOWNER'S INSTRUCTION MANUALIt is of vital importance, before attempting tooperate your engine, to read the general'SAFETY INSTRUCTIONS AND WARNINGS'section on pages 2-5 of this booklet and to strictlyadhere to the advice contained therein.

•Also, please study the entire contents of thisinstruction manual, so as to familiarize yourselfwith the controls and other features of theengine.

• Keep these instructions in a safe place so thatyou may readily refer to them whenevernecessary.

• It is suggested that any instructions suppliedwith the vehicle, radio control equipment, etc.,are accessible for checking at the same time.

CONTENTSSAFETY INSTRUCTIONS ANDWARNINGS ABOUT YOUR O.S. ENGINE - - - - 2-5

ENGINE CONSTRUCTION---------------- 6

NOTES WHEN APPLYING AN ELECTRICSTARTER - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7

ABOUT THE ENGINE------- - - - - - - - - - - - - - 8

BEFORE STARTING-------------------9-11

BASIC ENGINE PARTS - - - - - - - - - - - - - - - - - - 11

CARBURETOR CONTROLS---------------12

GLOWPLUG------- - - - - - - - - - - - - - - - - - - - -13

INSTALLATION OF THE STANDARDACCESSORIES-- - - - - - - - - - - - - - - - - - - - - - - 14

INSTALLATION------------------------- 15

STARTING THE ENGINE & RUNNING-IN---16-19

FINAL ADJUSTMENT------------------20-22

CARBURETOR CLEANLINESS-------------22

CARE AND MAINTENANCE - - - - - - - - - - - - 23-24

CHECKING THE ENGINE - - - - - - - - - - - - - - - - - 24

GUARANTEE-----------------------25

TROUBLE SHOOTING-----------------26-29

ENGINE EXPLODED VIEW & PARTS LIST - - - 30-31

CARBURETOR EXPLODED VIEW &PARTS LIST-------------------------32-33

O.S. GENUINE PARTS & ACCESSORIES - - - - 34-35

THREE VIEW DRAWING-- - - - - - - - - - - - - - - - -36

1

SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINERemember that your engine is not a "toy", but a highly efficient internal-combustion machine whose power is capable of harming you, or others, if it ismisused.As owner, you, alone, are responsible for the safe operation of your engine, so actwith discretion and care at all times.If at some future date, your O.S. engine is acquired by another person, we wouldrespectfully 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 dangerwhich might arise through misuse or neglect.

WARNINGS

These cover events whichmight involve serious (inextreme circumstances, evenfatal) injury.

NOTESThese cover the many otherpossibilities, generally less obvioussources of danger, but which, undercertain circumstances, may alsocause damage or injury.

2

WARNINGSModel engine fuel is poi-sonous. Do not allow it tocome into contact with theeyes or mouth. Always storeit in a clearly marked con-tainer and out of the reachof children.

Model engine fuel is alsohighly flammable. Keep itaway from an open flame,excessive heat, sources ofsparks, or anything elsewhich might ignite it. Do notsmoke or allow anyone elseto smoke, near to it.

Never operate your engine in an en-closed space. Model engines, likeautomobile engines, exhaust deadlycarbon-monoxide. Run your engineonly in an open area.

Model engines generateconsiderable heat. Do nottouch any part of yourengine until it has cooled.Contact with the muffler(silencer), cylinder heador exhaust header pipe, inparticular, may result in aserious burn.

3

NOTESThis engine is intended for model cars.Do not attempt to use it for any otherpurpose.

Mount the engine in your modelsecurely, following the manufacturers'recommendations, using appropriatescrews and locknuts.

Install an effective silencer (muffler).Frequent close exposure to a noisyexhaust (especially in the case of themore powerful highspeed engines)may eventually impair your hearingand such noise is also likely to causeannoyance to others over a wide area.

The wearing of safety glasses is alsostrongly recommended.

Take care that the glowplug clip orbattery leads do not come into contactwith rotating parts. Also check that thelinkage to the throttle arm is secure.

For their safety, keep all onlookers(especially small children) well back(at least 20 feet or 6 meters) whenpreparing your model for running.

4

To stop the engine, fully retard thethrottle stick and trim lever on thetrans-mitter, or, in an emergency, cutoff the fuel supply by pinching the fueldelivery line from the tank.

Warning! Immediately after a glowplug-ignition engine has been run and is stillwarm, conditions sometimes existwhereby it is just possible for the engineto abruptly restart if it is rotated overcompression WITHOUT the glowplugbattery being reconnected.

NOTES

5

ENGINE CONSTRUCTION

With this engine, the piston willfeel tight at the top of its stroke(TDC) when the engine is cold.This is normal. The cylinder boreis a little tapered. The piston andcylinder are designed to achievea perfect running clearancewhen they reach their runningtemperatures.

Around TDC

Cylinder Liner

When the engine is cold. When the engine is hot.

Piston

Crankshaft

A little tapered

6

NOTES WHEN APPLYINGAN ELECTRIC STARTER

Do not over-prime. This couldcause hydraulic lock and damagethe engine on application of theelectric starter.

If over-primed, remove glowplug,close needle-valve and applystarter to pump out surplus fuel.Cover the head with waste toprevent pumped out fuel cominginto your eyes. NOTE

As delivered, the engine has itscarburetor lightly fit into its intake.Secure it changing its angleaccording to the car chassis.

7

ABOUT THE ENGINE

The MAX-21 VZ-B V-Spec is a high per-formance 3.5cc class power unit for one-eight-scale radio-controlled 'off-road' or'buggy' cars. It has been expressly de-signed for racing competitions.T-type plug (turbo plug) design improvesthe power, fuel consumption and durabili-ty.The new 21 C carburetor is supplied with8mm and 9mm dia. reducers to managedifferent course conditions.

Standard accessories

Cylinder-head gasket (0.1mm) 1 sheet

Exhaust Seal Ring 1 piece

Carburetor Reducer 8mm (Red) 1 piece

Dust Cap 03,016,018 every Ipiece

Glow Plug P3 T-type head (Turbo head)1piece(Hot Type)

(w/ "0" Ring)

8

BEFORE STARTINGTools, accessories, etc.The following items arenecessary for operating the engine.

Optional Extras

T-2050 TUNED SILENCER ASSEMBLYThis is designed specifically for 3.5cc 'off-road'model car engines.

GLOW PLUG T-Type (Turbo Plug)P3 is supplied with the engine. Asreplacement, suggested O.S. plugs areP3 and P6.SUPER AIR CLEANER 203 ASSEMBLYThis is a heavy-duty wet typeair cleaner designed specificallytor 3.5cc 'off-road' model carengines.

T-2050 EXHAUST HEADER PIPE ASSEMBLYThis is designed to use with the T-2050Tuned Silencer

T-2050 TUNED SILENCER COMPLETE SETThis is a set of T-2050 Tuned Silencer and T-2050 Exhaust Header Pipe Assembly.

TOOLSHEX WRENCHNecessary for engine installation.1.5mm, 2mm, 2.5mm, 3mm opposite side

SCREWDRIVERNecessary for carburetor adjustments.No.1,No.2,etc

9

LONG SOCKET WRENCH WITH PLUG GRIP REMINDER!Recommended for easy removal andreplacement of the angled and recessedglowplug, the O.S.Long Socket Wrenchincorporates a special grip.

Items necessary for startingFUELGenerally, it is suggested that the user selects a fuelthat is commercially available for model two-strokeengines and contains 10-30% nitromethane. As astarting point, we recommend a fuel containing 20%nitromethane, changing to a fuel containing morenitro if necessary. When the brand of fuel ischanged, or the nitro content increased, it isadvisable to repeat the running-in procedurereferred to in the RUNNING-IN paragraphs. Pleasenote that with high-nitro fuels,although power may be increasedfor competi t ion purposes,glowplug elements do not last aslong and engine life will beshortened.

Model engine fuel is poisonous. Donot allow it to come into contact withthe eyes or mouth. Always store it in aclearly marked container and out ofthe reach of children.

Model engine fuel is also highlyflammable. Keep it away from openflame, excessive heat, sources ofsparks, or anything else which mightignite it. Do not smoke or allow anyoneelse to smoke, near to it.

FUEL FILTERTo fit in the fuel line between fueltank and carburetor to preventdust coming into the carburetor.

GLOWPLUG IGNITERCommercialy available handyglowplug heater in which theglowplug battery and batteryleads are integrated.

10

STARTER BOXFor starting the engine.

7.2V BATTERIES FOR STARTER BOX

Batteries for starter box.Select according to thestarter box used. Be sure tofull charge before using.

FUEL PUMPFor filling the fuel tank, a simple,polyethylene "squeeze" bottle,with a suitable spout, is required.

SILICONE FUEL LINEHeatproof silicone tubing ofapprox. 5mm o.d. and 2mm i.d.is required for the connectionbetween the fuel tank andengine.

BASIC ENGINE PARTSHeatsink Head

Crankshaft

CarburetorType 21 C

Exhaust

Cover Plate

Mounting LugsCrankcase

11

CARBURETOR CONTROLS

Carburetor Reducer

Needle Valve

Mixture Control ValveAssembly Screw

Throttle StopScrew

Metering Needle

Thermo Insulator

Four adjustable controls are provided onthis carburetor.

The Needle-Valve:For adjusting the mixture strength when thethrottle is fully open.The Mixture Control Screw:For changing the mixture strength at midspeed and acceleration. (Do not rotate thescrew more than one turn.)The Metering Needle:For adjusting the mixture strength at part-throttle and idling speeds, to obtain steadyidling and smooth acceleration to midspeeds.The Throttle Stop Screw:For setting the minimum idling speed:

NOTE: Readjustment may be necessary,occasionally to allow for changes in fuelformula gear ratio or clutch engagementpoint.

12

GLOWPLUGSince the compatibility of glowplug and fuelmay have a marked effect on performance andreliability, it may be worthwhile to choose theR/C type plug found most suitable aftertests. Recommended O.S. plugs are P3 and P6.Carefully install plug finger-tight, before finaltightening with the correct size plug wrench.

The role of the glowplugWith a glowplug engine, ignition is initiated by theapplication of a 1.5-volt power source. When thebattery is disconnected, the heat retained within thecombustion chamber remains sufficient to keep theplug filament glowing, thereby continuing to keep theengine running. Ignition timing is 'automatic' : underreduced load, allowing higher rpm, the plug becomeshotter and, appropriately, fires the fuel/air chargeearlier; conversely, at reduced rpm, the plug becomecooler and ignition is retarded.

Glowplug lifeParticularly in the case of very high performanceengines, glowplugs must be regarded as expendableitems. However, plug life can be extended and engineperformance maintained by careful use, i.e.:

Install a plug suitable for the engine.Use fuel containing a moderate percentage ofnitromethane unless more is essential for racingevents.Do not run the engine too lean and do not leave thebattery connected while adjusting the needle.

When to replace the glowplugApart from when actually burned out, a plug mayneed to be replaced because it no longer delivers itsbest performance, such as when:

Filament surface has roughened and turned white.Filament coil has become distorted.Foreign matter has adhered to filament or plugbody has corroded.Engine tends to cut out when idling.Starting qualities deteriorate.

13

INSTALLATION OF THE STANDARD ACCESSORIESFitting the glow plug. Insert P3 plug suppliedinto heatsink-head carefully, making sure thatit is not cross-threaded before tightening firmly.(All the O.S. T-Type plugs including the P3 arenot supplied with a washer.)

Glowplug

ExhaustSeal Ring

Install the exhaust sealring supplied.

The engine is fit with one each of 0.1mm and 0.2mmcylinder-head gasket when it leaves the factory.Another 0.1mm head gasket is supplied with theengine. You may add it at initial running-in, when aglow plug tends to burn out due to high temperatureand / or high humidity or when you prefer fueleconomy to power.

Fitting the carburetor reducerReplace the reduce according to the courseconditions.

9mm (Blue)Fitted with the carburetor when leaves the fac-tory. Suitable for high speed (wide) and flatcourse which requires power.

8mm (Red)Supplied with the engine. Replace when re-quired. Suitable for technical (narrow) andbumpy course and when less fuel consumptionis more important.

INSTALLATION OF THE DUST CAP SETIn case engine is kept, an exhaust port, a carburetor,etc. are equipped and penetration of the foreignsubstance inside engine is prevented.

14

INSTALLATION OF THE CARBURETORAs delivered, the engine has its carburetor lightlyinstalled in the intake boss. Secure it as follows.1. Loosen the retainer screw, rotate the

carburetor to its correct position and makesure that it is pressed well down into theintake boss, compressing the rubber gasket,before retightening screw.

2. Rotate the retainer screw gently until itstops, then tighten a further 120-180 degrees.Do not overtighten the screw as this willdamage the carburetor body.

ENGINE INSTALLATIONMake sure that the vehicle's engine mountingsurfaces are level and in the same plane. Poorinstallation may cause distortion of thecrankcase, bearings, etc., resulting in erraticrunning and loss of performance.The recommended screws for securing theengine are 3mm or 4-40 steel Allen hexagonsocket type.If existing holes in the engine mount do not alignperfectly with engine mounting lugs, enlargethem slightly with a needle-file so that screws arein alignment with the mounting holes.

Rotate the retainer nutgently until it slops.

Tighten a further120-180 deg.

Do not allow bottomof crankcase totouch chassis.

Chassis

Chamfer inside edges of bearers.

15

STARTING THE ENGINE & RUNNING-IN ("Breaking-in")For long life and high performance, everyengine needs to be 'run-in' or 'broken-in'. Withcare, running-in of the MAX-21VZ-B V-Speccan be carried out with the engine installed inthe vehicle. Be sure to install the air-cleaner onthe carburetor and use a muffler-pressurizedfuel system.The following procedure is suitable for theseengines when the O.S. T-2050 tuned silencerand a fuel containing up to 30% nitromethaneare used.

Fill the tank completely with fuel.

Fuel Pump

Fuel Tank

Temporarily remove the glowplug to checkthat it glows bright red when energized.

Element glows when energized.

Replace the plug when theelement does not glow or isburnt out.

Glow Plug Igniter

Pliers

16

Turn the needle-valve clockwise slowly untilit stops. This is the fully closed position.Do not force to turn further.

Open the Needle-Valve 3 turns from the fullyclosed position.

Switch on the transmitter and receiver andset the throttle very slightly open from theidling position.

Needle Valve

Open

Throttle opening at idlingapprox 0.3-0.5mm

Close

Note:Throttle opening at idling should bechecked before fitting an air cleaner.

Turn the engine with starter box to draw thefuel into the engine.

Starter Box

Deliver fuel into the carburetor.

Fuel tank sideFuel

17

Now connect glowplug battery lead to heatthe plug filament and start the engine.

Attention:It is vitally important to set thethrottle at the correct positionbefore starting the engine. If theengine is allowed to run with thethrottle too far open under "no load" conditions(i.e. with the driving wheels not in contact with

When the engine starts,first allow it to operate inshort runs at the very richstarting settings, with theglowplug battery stillconnected and the drivingwheels clear of the ground.The rich mixture will, underthese conditions, provideadequate lubrication andcooling, indicated byprofuse smoke from theexhaust.Next, disconnect the glowplug battery andtry running the car on the track. If the enginestalls, open the throttle fractionally, but try tokeep the engine running as rich as possible:if it stops because of being excessively over-rich, close the Needle-Valve 30° and tryagain.

Glow Plug Igniter Air Cleaner

Starter Box

18

Run the car on the track until one tank of fuelhas been consumed, then close the Needle-Valve 30° and run the car for another fulltank of fuel. Repeat this procedure until 1/2gallon of fuel have been consumed, duringwhich time the throttle may be opened forbrief bursts of increased power.

Needle

The position of the needle-valvewhen starting the engine.

Close the needle-valve approx.30° after running the vehicle torone full tank of fuel.Repeat this procedure severaltimes.

Note:If the engine should need to be disassem-bled (e.g. for cleaning or minor parts re-placement), it is advisable to return the nee-dle-valve to the original rich, starting set-ting and check whether further running-intime is required before the car is raced

again. In the event of any major workingparts (e.g. piston/cylinder liner assembly)being replaced or the fuel being changed,especially to high nitro fuel, the completerunning-in should be repeated.

To stop the engine, close the throttle toidling speed, then shut it off completely withthe trim lever on the transmitter. To cut offthe fuel supply, pinch the fuel delivery tubeto the carburetor.

Fuel

Warning!Do not touch rotating parts, engine and si-lencer when stopping the engine as theybecome very hot, and contact with themmay result in a serious burn.

Air Cleaner

19

FINAL ADJUSTMENTFinal adjustment should be carried out only afterthe running-in has been completed.

Needle Valve

Needle Valve

More fuel Less fuel

OpenOpen Close

More fuel

Metering Needle

Metering Needle

Run the vehicle (with throttle fully open) overthe longest available straight course, in orderto observe the model's speed. Next returnthe car to the starting point, close the Needle-Valve 30° and repeat the run, taking note ofthe improvement in performance.

Continue with further runs, graduallyreducing the Needle-Valve setting andaiming to achieve the highest straight-linespeed. Remember, however, that, if theNeedle-Valve is shut down too far, theengine will overheat and, accompanied byvisibly diminished exhaust smoke, the modelwill lose speed. At this point, throttle downimmediately, stop the vehicle and reopen theNeedle-Valve 45-90° .

Close

Less fuel

20

With the engine running, close the throttleand allow it to idle for about five seconds,then reopen the throttle fully. If, at this point,the engine puffs out an excessive amount ofsmoke and the vehicle does not acceleratesmoothly and rapidly, it is probable that theidling mixture is too rich. In this case, turnthe Metering Needle clockwise 45-90°. If, onthe other hand, the engine tends to speed upmomentarily and then cut out abruptly whenthe throttle is opened, the idling mixture istoo lean. Correct this by turning the MeteringNeedle counter-clockwise 45-90°.

NOTE:Metering Needle adjustment should bemade in steps of not more than 45-90°,carefully checking the effect.on throttleresponse, of each small adjustment.

Carry out adjustments patiently, under actualrunning conditions, until the engine respondsquickly and positively to the throttle control.

Warning!Mixture adjustments (whether via theMetering Needle, or the Needle-Valve)cannot be made accurately under 'no-load'conditions, which, in any case, are notadvised, since such operation carries therisk of seriously damaging the enginethrough over-revving and overheating.

With the optimum mixture control position,light smoke is visible during high speedrunning,and the engine rpm increasessmoothly during acceleration. Rememberthat, if the engine is operated with the fuel/airmixture slightly too lean, it will overheat andrun unevenly. As with all engines, it isadvisable to set both the needle-valve andmetering needle very slightly on the rich sideof the best rpm setting, as a safety measure.

If the engine runs too fast with the throttleclosed, the throttle stop screw should beturned counter-clockwise to allow the throttleopening to be reduced.

21

Finally, beyond the nominal break-in period,a slight readjustment toward a leaner needlesetting may be required to maintainmaximum performance.

CARBURETOR CLEANLINESSThe correct functioning of the carburetordepends on its small fuel orifices remainingclear.

REALIGNMENT OF METERING NEEDLE ANDMIXTURE CONTROL VALVE

In the course of making carburetoradjustments, it is just possible that the MeteringNeedle and the Mixture Control Valve may beinadvertently screwed in or out too far andthereby moved beyond its effective adjustmentrange.The basic positions can be found by rotatingthe Metering Needle until its slotted head isflush with the ball link body.

Mixture Control ValveCarburetor Body

Rotate the MeteringNeedle until its slottedhead is flush with theball link body. This is thestandard position.

Metering Needle

Ball LinkCarburetor Body

Slide Valve

First rotate the MixtureControl Valve until its slottedhead is flush with thecarburetor body. Then screwthe valve in exactly 1 turn.This is the standard position.

22

CARE AND MAINTENANCE1.The minute particles of foreign matter, that are

present in any fuel may, by accumulating andpartially obstructing fuel f low, cause engineperformance 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 to the pickup tubeinside your refueling container, will prevent the entryof foreign material into the fuel tank. It is alsorecommended that a good in-line filter be installedbetween the tank and carburetor.

2. Do not forget to clean the filters regularly to removedirt and lint that accumulate on the filter screens.Also, clean the carburetor itself occasionally.

3. At the end of each operating session, drain out anyfuel that may remain in the fuel tank.Afterwards,energize the glow-plug and try to restartthe engine, to burn off any fuel that may remaininside the engine. Repeat this procedure until theengine fails to fire. Do this while the engine is stillwarm.

4. Then, inject some after-run oil into the engine, androtate the engine with an electric starter for 4 to 5seconds to distribute the oil to all the workingparts.

Note:Do not Inject after-run oil Into the carburetor asthis may cause the 0-rlngs inside the carburetorto deteriorate. These procedures will reduce therisks of starting difficulties or corrosion after aperiod of storage.5. Finally, when cleaning the exterior of the engine,

use methanol or kerosene. Do not use gasoline orany solvent that might damage the silicone fueltubing.

Caution:The rear crankshaft bearing of this engine uses aspecial plastic retainer. If the front housing needsto be heated to remove or replace the bearing, donot allow the bearing to exceed 120"C (248'F),otherwise it may be damaged and renderedunserviceable.

23

Fitting Dust CapsWhen storing the engine, fit it to exhaustport, carburetor, etc. to prevent dust enteringinside the engine.

CHECKING THE ENGINEEngine will not develop normal performanceafter long time running due to wearing of parts.It is suggested to replace necessary parts whenthe following symptoms are detected.

Engine sound changes and easily overheats.

Power has dropped extremely.

Idling is unstable and/or engine tends to stopat idling.

In most cases, ball bearings, cylinder & pistonassembly, connecting rod and/or crankcase havebecome worn out or abnormal. Check theparts carefully and replace them if necessary.

24

GUARANTEEThis engine is constructed from the very bestmaterials available and to the very highestengineering standards, using the most advancedprecision machinery. However, the extremely highstresses imposed by car racing operation under verysevere conditions, as well as stresses which areexacerbated by the use of powerful fuels containingvery high concentrations of nitromethane, constitutehazards which are beyond a manufacturer's control.Accordingly, we regret that it is not possible to extendour usual warranty terms to this particular engine -i.e.no guarantee is offered against material wear, ordamage resulting therefrom, in actual use.

25

TROUBLE SHOOTING

Fuel tank is empty.Fuel not reaching the engine.

Fill the tank with fuel and repeatPriming procedure.Replace glowplug.Recharge or replace the battery.

Glowplug element is burnt out.Glowplug battery dischargedClogged fuel filterAir cleaner and silencer inside is dirty.

Clean or replace fuel filter.Replace cleaner element and clean inside silencer.

Remove glowplug and pump excess fuel.Over priming

Fuel tubing is disconnected.Fuel tubing is kinked, split or has a hole.

Connect fuel tubing securely.Check the tubing carefully and replace if necessary.Return the metering needleand mixture control valve to basic position.

Re-linkage after setting servo at neutral.

Mare sure it rotates counter clockwise seenfrom crankshaft side.Reverse rotating direction of starter box.

Incorrect servo linkage

Incorrect carburetor settings

Engine fails to fire.

26

Fit 0 rings to the tank screws toprevent bubbles.

Do not disconnect plug battery and wait untilr.p.m. become stable.Too immediately disconnecting plug battery

Fuel in the tank extremely bubbled

Adjust the tension of clutch spring.Incorrect clutch release

Engine overheated Wait until engine is cooled.

Clogged fuel filterAir cleaner and silencer inside is dirty.

Clean or replace fuel filter.Replace cleaner element and clean inside silencer.

Deteriorated glowplug Replace glowplug.

Fill the tank with fuel.Insufficient fuel in the tank.

Engine fires intermittently but does not run.

27

Unsuitable glowplug Use suggested glowplug in the instructions.

Do not use extremely high nitro or low oil fuel.

Add suitable load.

Install silencer securely.

Unsuitable fuel

Extremely light flywheel

Silencer is disconnected or has play

Unstable idling

Not reaching expected peak r.p.m.

Insufficient warming up or running-in.

Silencer or manifold is not securely connectedor disconnected.

Fuel tubing from tank to is split or broken.

Set the needle only after warming up.Complete running-in.Replace seal ring.Check the connections and secure them.

Replace the tubing.

28

Incorrect carburetor fitting Fit carburetor securely.

Incorrect setting of transmitter Exponential function.

Too much throttle opening at idling.

Poor r.p.m. drop

Check the transmitter setting.

Close metering needle to adequate positionto lower idling r.p.m.

Readjust low r.p.m. range with meteringneedle and mixture control valve.

Replace glowplug.Deteriorated glowplug

Incorrect carburetor settings

Poor response

29

ENGINE EXPLODED VIEW

17

1

2

3

65

67

9

C.M2.6X7

16

1514

13

12

11

10

C.M2.6X18

8

4

CM3X18

*Type of screw C—Cap Screw M--0val Fillister-Head ScrewF-Flat Head Screw N-Round Head Screw S-Set Screw

ENGINE PARTS LIST

No.1 221050002 221051003 1237640104567891011121314151617

Code No.

221030102390600023817000237550002381805023715000239817002373100023751010237300102210200023764020237570002376301071641300228261407153300022884250

DescriptionOuter HeadInner HeadHead Gasket (2pcs.)Cylinder & Piston AssemblyPiston PinPiston Pin Retainer (2pcs.)Connecting RodCarburetor Complete (Type 21 C)Carburetor Sealing GasketCarburetor Retainer AssemblyCrankshaft Ball Bearing (Front)CrankcaseCrankshaft Ball Bearing (Rear)CrankshaftCover GasketCover PlateScrew SetGlow Plug T-P3Exhaust Seal RingCarburetor Reducer 8mm (RED) w/ "0" Ring (2pcs.)Dust Cap Set ( 3mm, 16mm, 18mm)

The specifications are subject to alteration for improvement without notice.

CARBURETOR EXPLODED VIEW

* Type of screwC. Cap Screw M Oval Fillister-Head ScrewF.FIat Head Screw N . Round Head Screw S.Set Screw

32

CARBURETOR PARTS LISTNo.1

1-11-22

2-12-22-32-434567

7-189101112

Code No.23781600460663192278180023618190236181974606631923618194238181767153301023818500238181302378120023818340278818202288422023781400237811102901501923818190

DescriptionMixture Control Valve Assembly

"0" Ring (L) (2pcs.)"0" Ring (S) (2pcs.)

Needle Valve AssemblyNeedle Assembly

"0" Ring (2pcs.)Needle Holder Assembly

Fuel Inlet (No.9)Carburetor Reducer 9mm (BLUE) w/ "0" Ring (2pcs.)Throttle Stop ScrewCarburetor Body (w/Thermo Insulator)Slide ValveMetering Needle Assembly

"0" Ring (2pcs.)Dust CoverBall Link No.3Thermo InsulatorCarburetor Rubber GasketCarburetor Sealing Washer

The specifications are subject to alteration for improvement without notice.

33

34

O.S. GENUINE PARTS & ACCESSORIES

GLOWPLUGP3 P6

(71641300) (71641600)

T-2050 EXHAUST HEADER PIPE ASSEMBLY(72106150)

Exhaust Header Pipe(72106155)

Header Pipe Spring (2pcs.)(72101272)

Exhaust Seal Ring (2pcs.)(22826140)

T-2050 TUNED SILENCER ASSEMBLY(72106060)

T-2050 TUNED SILENCERCOMPLETE SET(72106070)

T-2050Tuned Silencer Assembly(72106060)

T-2050Exhaust Header Pipe Assembly(72106150)

T-2050 Tuned Silencer Body(72106061)

Pressure Nipple(72106041)

Exhaust Seal Ring (2pcs.)(22826140)

Joint Spring (3pcs.)(72106042)

The specifications are subject to alteration tor improvement without notice.

The specifications are subject to alteration for improvement without notice.

LONG SOCKET WRENCHWITH PLUG GRIP(715210001

CRANKSHAFT CLAMP1521(71530200)

DUST CAP SET3mm (5pcs.) (73300305)

8mm (3pcs.) (73300812)16mm (3pcs.) (73301512)18mm (3pcs.) (73301812)

M2.6x7(10pcs.)(79871020)

CAP SCREW SET

T-2030 TUNED SILENCER(72106030)

21 RZEXHAUST HEADER PIPE(72101270)

SUPER JOINT TUBE 21(72106300)

SUPER AIR CLEANER 203(72413000)

203 Filter Element (4pcs.)(72413200)

EXHAUST SEAL RING(22826140) (2pcs.)

O.S. GENUINE PARTS & ACCESSORIES

35

THREE VIEW DRAWINGSPECIFICATIONS

DisplacementBoreStrokePractical R.P.M.Power outputWeight

3.46cc(0.211cu.in.)16.6mm (0.654in.)16.0mm (0.630in.)3,000-40.000 r.p.m.2.48ps / 33.000 r.p.m.360g (12.7oz.)

36

Dimensions (mm)

6-15 3-Chome Imagawa Higashisumiyoshi-kuOsaka 546-0003, Japan TEL. (06) 6702-0225

FAX. (06) 6704-2722URL: http://www.os-engines.co.jp

(C) Copyright 2004 by O.S.Engines Mfg. Co.. Ltd. All rights reserved. Printed in Japan. 60091490 050400