TRIUMPH UNIT CONSTRUCTION 650 AND 750CC · PDF fileTRIUMPH UNIT CONSTRUCTION 650 AND 750CC TWINS Bonneville T120 Thunderbird 6T Bonneville Bonneville T140V MODEL Trophy TR6 T120V Tiger

Triumph 650 & 750 Twins iVIOTORCYCLE

cover. Clutch operating cam and gearchange ratchets (Fig, TM3-30) areremoved with the outer cover.

To remove the gear box inner coverand gears (Fig. TM3-31), remove thecomplete clutch assembly and unscrewthe output sprocket retaining nut.Remove the two screws attaching innercover to transmission housing andremove the inner cover complete withcam plate, shift forks, gears and shafts.

To remove bearings (3, 12 & 36—Fig.TM3-32), the respective housing shouldbe heated to approximately 100° C(212° F). On all models except 3TA or5TA, the needle bearing (12) shouldproject 0.073-0.078 inch into thehousing. Installation should be accom-plished with a drift shown in Fig. TM3-33,

Bushing (5—Fig, TM3-32) should beinstalled with oil groove toward gear

end of output shaft (4). All bushingsmust be reamed after installation.Refer to the following and Fig, TM3-32for finished bushing specifications:Bushing (5)—

diameter 0.752-0.753 in.Clearance on shaft

(7) 0.0020-0,0035 in.Protrusion % in.

Bushing (12) for 3TA and 5TA modelsonly—

Diameter 0.6865-0.6885 in.Bushing (20) for 3TA and 5TA modelsonly—

Diameter 0.689-0.690 in.Bushing (18)—

diameter 0.689-0.690 in.Clearance on shaft

(15) 0,0015-0.0030 in.Free length of kick starter spring (22

—Fig. TM3-32) is Vz inch. Free lengthof ratchet springs (3—Fig. TM3-30) is 1

1/16 inches. Free length of springs (8)is 1% inch. Finished diameter ofbushing (6) should be 0.623-0.624 inchand shaft (2) should have 0.001-0.003inch clearance.

The gears and shafts should be as-sembled in the inner cover as removed.Check operation before installing.Shift forks (28 & 30—Fig. TM3-32)must be installed correctly. To check,shift the cam plate (25) to both ex-tremes (first and fourth gears) andcheck position of the guide rollers inthe cam plate grooves. If shift forks arecorrectly installed, both rollers willreach both ends of the grooves. If move-ment of either roller is incorrect, re-move shift forks (28 & 30) and ex-change places. NOTE: Shift forks arenot interchangeable. The rollers forcam plate are offset.

TRIUMPH UNIT CONSTRUCTION650 AND 750CC TWINS

Bonneville T120Thunderbird 6T Bonneville Bonneville T140V

MODEL Trophy TR6 T120V Tiger TR7VDisplacement^-cc 649 649 744*Bore—mm 71 71 76*Stroke—mm 82 82 82Number of cylinders 2 2 2Ignition—

Spark plug type—Champion N-4 N-4 N-3Electrode gap—mm 0.5 0.5 0.635

Inch 0.020 0.020 0.025Point gap—mm 0.35-0.40 0.35-0.40 0.35-0.40

Inch 0.014-0.016 0.014-0.016 0.014-0.016Valve clearance (cold)

Intake-mm 0.05 0.04 0.20Inch 0.002 0.002 0.008

Exhaust-mm 0.10 0.10 0.15Inch 0.004 0.004 0.006

Electrical system voltage ** 12 12 12Battery terminal grounded Positive Positive PositiveTire size-front . t 3,25x19 3.25x19

Rear t 4.00x18 4.00x18Tire pressure—

Front—kg/cm2 1.68 1.68 1.68Psi 24 24 24

Rear—kg/cm2 1.75 1.75 1.68Psi .. 25 25 24

Rear chain free play t t t t t tNumber of speeds 4 5 5*Before serial numbers T140V XH22019 and TR7V AH24044, standard cylinder bore was 75mmand displacement was 724cc,**Early models are equipped with 6 volt electrical system.tVarious tire sizes have been used including 3.25 x 18,3.50 x 18,4.00 x 18,3.25 x 19 and 3.50 x 19.ttRear chain free play should be % inch (18mm) with weight on wheels or 1% inches (43mm) withmotorcycle on center stand.Illustrations courtesy of Norton Triumph Corp.

MArNTENANCESPARK PLUGS. Recommended

spark plug for normal use is ChampionN58R for T120TT models. ChampionN-4 for other 650cc models; Champion

N-3 for all 750cc models. Spark plugsare 14mm with % inch reach and heatrange may vary depending upon use.Electrode gap should be 0.020 inch(0,5mm) for all 650cc models; 0,025inch (0,635mm) for 750cc models.

CARBURETOR. Amal Monoblocand Concentric carburetors are used.Bonneville T120 models use two car-buretors, all others use one. Refer tothe following specification data:

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SERVICE Triumph 650 & 750 Twins

Fig. TM4-1-Exploded view of typical Amal Mon-obloc carburetor used. Refer to Fig. TM4-2 for

view of Amal Concentric fioat carburetor.

1. Idle mixture need ie 11. Needle jet2. Jet block screw 13. Mainjet3. Throttle slide 14. Throttle spring4. Clip 15. Jet block5. Valve needle 16 Float6. Pilotjet 17. Inlet valve7. Idle speed stop screw 19, Primer8. Fuel filter 20. Choke valve

10. Jetholder 21. Cableguide

6T (Serial No. DUlOl and up)Refer to Fig. TM4-1Model 376/303Mainjet (13) 230Needle jet (11) 106Valve needle (5) CThrottle slide (3) 376/4Pilotjet (6) 25Clip (4) in third groove from top ofneedle (5).

TR6 (Serial No. DUlOl to DU5824)Refer to Fig. TM4-1Model 376/Mainjet (13) 250Needle jet (11) 106Valve needle (5) CThrottle slide (3) 376/3V2Pilotjet (6) 25Clip (4) in third groove from top ofneedle (5).

TR6 (Serial No. DU5825-DU44393)Refer to Fig. TM4-1Model 389/97Mainjet (13) 310Needle jet (11) 106Valve needle (5) DThrottle slide (3) 389/3^2Pilotjet (6) 25Clip (4) in top groove of needle (5).

TR6 (Serial No. DU44394-DU66245)Refer to Fig. TM4-1Model 389/239

Mainjet (13) 330Needle jet (11) 106TValve needle (5) DThrottle slide (3) 389/4Pilotjet (6) 25Clip (4) in top groove of needle (5).

T120 (Serial No. DU101-DU5824)Refer to Fig. TM4-1Model 376/Mainjet (13) 240Needle jet (11) 106Valve needle (5) CThrottle slide (3) 376/3^2Pilotjet (6) 25Clip (4) in second groove from top ofneedle (5).

T120 (Serial No. DU5825-DU66245)and T120R (Serial No. DU24875-DU44393)Refer to Fig. TM4-1Model 389/203Mainjet (13) 260Needle jet (11) 106Valve needle (5) DThrottle slide (3) 389/3Pilotjet (6) 25Clip (4) in third groove from top ofneedle (5).

T120R (Serial No. DU44394-DU66245) and T120TT (Serial No.DU24875-DU66245)Refer to Fig. TM4-1Model 389/95Mainjet (13) 330Needle jet (11) 106Valve needle (5) DThrottle slide (3) 389/3V2 or 389/4Pilotjet (6) 25Clip (4) in second groove from top ofneedle (5).

T120R (Serial No. 66246 and up)Refer to Fig. TM4-2Model—left 930/10

Right 930/9Mainjet (13) 210 or 220Needle jet (11) 0.106 or 0.107Throttle slide (3) 2y2 or 3Pilotjet (6) 20Clip (4) in second groove from top ofneedle (5).

T140V (Before Serial No.XH220019)Refer to Fig. TM4-2Model—left 930/88

right 930/87Mainjet (13) 210Needle jet (11) 106Throttle slide (3) 3Clip (4) in second groove from top ofneedle (5).

T140V (After Serial No. XH22018)Refer to Fig. TM4-2Model—left 930/93

right 930.92Mainjet (13) 190

Fig. TM4-2~Exploded view of Amai carburetorwith concentric float chamber.

1. Idle mixture needle2. Float chamber3. Throttle slide4. Clip5. Valve needle6. Pilotjet7. Idle sp>eed stop screw8. Fuei filter9. Baniobolt

10. Jet holder

11. Needle jet13. Mainjet14. Throttle spring15. Cap16. Float17. Fuel inlet needle18. Float pivot19. Primer20. Choke valve21. Cable adjuster

Needle jet (11) 106Throttle slide (3) 3Clip (4) in second groove from top ofneedle (5).

TR7VRefer to Fig. TM4-2Model 930/89Mainjet (13) 280Needle jet (11) 106Throttle slide(3) 3^^Clip (4) in second groove from top ofneedle (5).

On all models, idle mixture is ad-justed at needle (1—Fig. TM4-1 orTM4-2). Idle speed is adjusted at screw(7). On models with dual carburetors,the carburetors must be synchronizedto open exactly the same amount byadjusting the cable guides (21) at thetop of each carburetor. Idle mixture oncarburetor is more easily adjusted afterdisconnecting the spark plug wire fromthe other cylinder.

IGNITION AND ELECTRICAL.Ignition breaker point gap should be0.014-0.016 inch for all models. Theignition breaker point cam and ad-vance weights are mounted on theright end of the exhaust camshaft. Ig-nition timing for the right cylinder isadjusted by moving the breaker pointbase plate after removing the small

333


1Fig. TM4-4-The Ignition cam and advance as-sembly is mounted on the right end of the cam-shaft. Black and yellow wire goes to breakerpoints (3) and black and white wire goes to

breaker points (4).

Fig. TM4-7-Coils (C) for models with AC (energytransfer) Ignition are different than coils for bat-

•. tery IgniUon models.

round cover from the right side. It maybe necessary to vary the breaker pointgap on the second set of breaker pointsin order to set ignition timing for theleft cylinder.

Ignition automatic advance range incamshaft degrees {V2 of crankshaft de-grees) is stamped on the back of thebreaker cam. Standard ignition timingis as follows:

6T (Serial No. DU101.DU5824)Crankshaft degrees BTDC—

Static 7°Full advance 35°

Advance range stamped on cam .. 14°Piston position BTDC—

Static 0.015 inch

6T (Serial No. DU5825-DU44394)Crankshaft degrees BTDC—


Advance range stamped on cam ,, 12°Piston position BTDC—

Static 0,038 inch

Fig. TM4-8-The peg (P) on the primary drivesprocket should be at approximately 9 o'clockposition when the crankshaft Is at top dead

center (TDC).

TR6 and T120(Serial No. DU101-DU5824)Crankshaft degrees BTDC—


Advance range stamped on cam .. 14°Piston position BTDC—

Static 0.038 inch

TR6 and T120 Models with BatteryIgnition (Serial No. DU5825 and up)Static 15°Full advance 39°Advance range stamped on cam ., 12°Piston position BTDC—

Static 0.068 inch

TR6 and T120 Models with EnergyTransfer Ignition (Serial No.DU44395 and up)Crankshaft degrees BTDC—

Static , . , , . . , 29°Full advance 39°

Advance range stamped on cam , . , . 5°Piston position BTDC—

Static 0.25 inch

TR7Vand T140VCrankshaft degrees BTDC—

Static 14°Full advance , . 38°

Advance range of cam 12°Piston position BTDC—

Static 0.060 inch (1.5mm)

Full advanced ignition timing shouldoccur at 35° (crankshaft degrees) BTDCfor all 6T models; 39° BTDC for all TR6and T120 models; 38° BTDC for allTR7V and TRHOV models. Full ad-vanced ignition timing can be checkedusing a degree wheel mounted on theright end of exhaust camshaft and apower timing light.

All models are equipped with an al-ternator mounted at left end of crank-shaft which charges the battery (if soequipped) via a full wave rectifier. On

later models, current is controlled by azener diode after being rectified. Clear-ance between alternator coil poles androtor should be 0.008 inch minimum allthe way around. Rotor retaining nutshould be torqued to 30 Ft.-Lbs. (4.1kg-m) for all 650cc models; 40 Ft.-Lbs.(5.5 kg-m) for all 750cc models. On allmodels, stator mounting screws shouldbe torqued to 20 Ft,-Lbs. after correctlycentered over the rotor. Make certainthat stator wires do not rub on the pri-mary chain. On models with AC (en-ergy transfer) ignition, the alternatorrotor must be correctly timed to theengine to provide the electrical currentfor ignition. Models with energytransfer ignition are equipped withspecial high tension ignition coilsshown in Fig. TM4-7 located under thefuel tank.

When assembling models with en-ergy transfer ignition, observe the fol-lowing: Install the primary drivesprocket with the rotor locating peg atapproximately 9 o'clock position whenthe crankshaft is at top dead center.Refer to Fig. TM4-8. The rotor hasthree holes marked "S", "M" and "R".The "S" position should be used withfull advanced ignition timing at 37°BTDC. The "M" position should be usedwith 39° BTDC full advanced ignitiontiming. The "R" position should be usedonly if full advance ignition timing isset at 41° BTDC,

NOTE: It is important that ignitiontiming is correctly set in relation to therotor location. The current generatedwhen the breaker points open may beinsufficient to fire the spark plugs ifbreaker points open too soon or too late.If one set of breaker points is faulty,both cylinders will be affected. If thebrown stop light wire is shorted, theengine will not run.

VALVE SYSTEM. The valve clear-ance should be set with engine cold. On650cc models, intake clearance shouldbe 0.002 inch (0.05mm) and exhaustc learance should be 0.004 inch(0.10mm), On 750cc models intakeclearance should be 0,008 inch(0.20mm) and exhaust should be 0.006inch (0.15mm). On all models, checkthe clearance of one valve when thesimilar valve for other cylinder is amaximum opening, EXAMPLE: Clear-ance for the inlet valve for the rightcylinder should be set when the inletvalve for the left cylinder is fully open.

LUBRICATION. On 650cc models,i;he engine uses a dry sump lubricationsystem. On models before serialnumber DU24874, capacity is 6 pints(2.8 liters); later models have capacityof 7V4 pints (3,4 liters). Use SAE 40 oil

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6 7 8 9 10 11

8 9 12 13 10 14 11

Fig. TM4'9~Drawing of engine reservoir andlines typical of 650cc models.

F, FilterP. Drain plug1. Reservoir to pressure

pump hose2. Oil manifold3. Oil return hose

4, Rocker arm lubricantline

5. Rear chain meteringneedle

6 Hose to rear chain Fig. TM4-10-The Oil pump is located at (P) and relief valve at (R). Exploded view of late type relief7, Breather (vent) hose

1, Drive block2, Pressure plunger3. Scavenge plunger4. Check valves

6 Gasket7. Valve body8. Gasket9. Relief valve plunger

10. Spring11. Cap12. Nut13. Auxiliary spring

14, Rubber sleeve15, Indicator shaft16, Cover17, "O"ring

Fig. TM4-11-Primary chaincase shouid be filled to levelof plug (L) through top plug(F). The chain tension ad-juster is located inside hole

for drain plug (D).

Fig. TM4-9A-Drawing of engine oil lines typicalof 750CC models. Frame tube Is reservoir.

D. DipstickF. FilterG, GasketsP. Drain plug1, Reservoir to pressure

pump hose

2, Oil manifold3, Oil return hose4, Rocker arm lubricant

line

above 90 degrees F.; SAE 30 oil from 32degrees F. to 90 degrees F. Oil levelshould be maintained lV̂ inches (4cm)below filler cap opening of reservoir.Oil reservoir is located on right sideunder the seat. Remove filter (F—Fig.TM4-9) from reservoir to drain oil andclean filter. The oil should be drained,filters cleaned and reservoir should befilled with new oil every 1500 miles.

On 750cc models, the engine isequipped with a dry sump lubricationsystem which contains 4.8 pints (2.27liters). Use SAE 20W/50 multi vis-cosity motor oil. Oil is contained in theframe tubes which forms the reservoir.Drain oil by removing plug (P—Fig.

TM4-9A). The oil should be drained,filter (F) cleaned and reservoir shouldbe filled with new oil every 1000 miles.Oil should be maintained betweenmarks on dip stick (D).

On all models, installation of hosesto and from the reservoir is important.Refer to Fig. TM4-9 and Fig. TM4-9A.Oil is drawn from the reservoir to thepressure pump through hose (1). Thescavenge pump delivers oil back to thereservoir from the engine through hose(3). Oil pumped by the scavenge pumpis also used to lubricate the rockerarms via hose (4). On some models, oilis metered by valve (5—Fig. TM4-9)and delivered to the rear chain throughhose (6). The engine will probably bedamaged because of lack of lubricationif hoses are attached incorrectly.

The oil pump is located on the rightcrankcase half under the timing gearcover and is driven by an eccentric pegon the nut retaining the timing gear tothe inlet camshaft. Normal oil pressure

is 20-25 psi at idle and 60-65 psi duringnormal running. Refer to Fig. TM4-10for exploded view of pump and reliefvalve. On early models (bottom of Fig.TM4-10), free length of relief valvespring (10) should be 31/32 inch andauxiliary spring (13) should be 9/32inch long. On models after serialnumber DU13375, relief valve spring(10—top of Fig. TM4-10) should be 117/32 inches long.

On 650cc models, oil in primarychain case should be drained every1000 miles. The primary chain caseshould be filled to level of plug (L—Fig,TM4-11) with SAE 20 oil.

On 750cc models, oil in the primarychain case is automatically maintainedat correct level by the engine lubri-cating system. Pour 150cc of engine oilinto the chain case before starting en-gine if chain case has been drained.

On all models, the gear box should bedrained every 6000 miles. The gear boxshould be filled with EP 90 gear lubri-

335

Triumph 650 & 750 Twins MOTORCYCLE

Fig. TM4-12-The gear box oil level plug is shownat (M) and drain plug at (D). Filler plug is located

at top near ctutch cable.

Fig. TM4-13-Clatch spring tension can be ad-justed as shown after removing the primary

chain cover. Refer to text.

cant until oil begins to flow from thelevel plug hole. When checking gearbox oil level, it is necessary to fill withoil until above the level pipe. Some oilwill be inside the pipe when level plugis removed. Refer to Fig. TM4-12.

CLUTCH CONTROLS. To adjustthe clutch, remove the plug from theside of primary chain case cover, loosenthe locknut and turn the adjustingscrew (A—Fig. TM4-11) in until resis-tance is felt. Back the adjusting screw(A) out 1 turn and tighten the locknut.Adjust the cable guide at hand leveruntil cable has Vs inch free play.

If clutch slips with controls properlyadjusted, remove the primary chaincase cover and adjust the spring pres-sure. Initial setting is with adjustingnuts flush with ends of studs. Each nutmust be adjusted to provide evenspring pressure. To check adjustmentof springs, shift transmission to neu-tral, disengage clutch and operate thekick starter. Check the pressure plateas it turns and make sure it does notwobble. If one section of pressure plateis higher than the rest, tum the springadjuster near the high spot in and re-check. To tum the adjusting nuts out,it is necessary to hold the springs downas shown in Fig. TM 4-13 to release thelocking lug on bottom of nut.

PRIMARY CHAIN. Tension of theprimary chain is adjusted by tumingadjuster (T—Fig. TM4-11) after re-moving drain plug (D). Special hex-agon headed screwdriver (part No.

336

Fig. TM4-14-Exptoded view of the front suspen-sion used on early models (before serial number

DU5825). Refer to Fig. TM4-15 for later type.

1. Killer plug2. Tube3. Spnntj4. Bottom bushing5. Washer6. Bu.shingnut7. Restriftor rcxl8. Washer9. Screw

10. Sleeve nut top11. Oil .seal12. Seal retainer sleeve

nut13. Top bushing14. Dampening sleeve1.5. Lower tube16. Drain plug17. Guide tube

D496) should be used to tum adjuster(T). The chain should have V2 inch freeplay as measured through the fillerplug hole (F). Make certain that pri-mary chain case is filled to level of plughole (L) with SAE 20 oil after adjust-ment is complete.

To remove the primary chain casecover, remove the left exhaust pipe,loosen the rear brake adjuster until thebrake pedal is clear of the primarycover and remove the left foot rest.Remove drain plug (D—Fig. TM4-11)and allow primary chain case to drain.Remove the two domed nuts and eightattaching screws, then lift off the chaincover. To remove the primary chain, itis necessary to remove the alternator,then remove the clutch, chain andcrankshaft sprocket together.

When assembling, tapered side ofspacer (5—Fig. TM4-24) must be in-stalled toward the sprocket. Refer toIGNITION AND ELECTRICAL para-graphs for installing alternator rotorand stator. Make certain that alter-nator wires can not rub on primarydrive chain. Install chain tension ad-juster and adjust the chain free playafter the chain case cover is installed.

SUSPENSION. Each front suspen-sion unit contains 150cc of oil on all 6T,TR6 and T120 models with internal

Fig. TM4-15-Exploded view of front suspensionused from serial number DC5825 to DU66245. Onsome models, restrictor valve may be typeshown in Fig. TM4-1B. Refer to Fig. TM4-14 for

legend.

17

18

23

20

Fig. TM3'16-Vlew of restrictor valve used onsome models. Body (23) is attactted to lowertube (15-Flg. TM4-15) with screw (9-Flg. TM4-1S)

and must be removed before disassembling.

1. Filler plug16. Rod17. Pin18. Cup19. Oil restrictor

20. Nut, . 21. Bushing

22. Restrictor cap23. Restrictar body


11

-13

Fig. TM4'17-Exploded view of front suspensionused on models from serial number DU66246.

Fig. TM4-18-Exploded view of front suspensionunit used on iate models.

1. Filler plug2. Tube3. Spring4. Bottom bushing5. Washer6. Bushing nut7. Restrictor9. Screw

11. Oilseal12. Seal retainer sleeve

nut13. Top bushing14. Dampening sleeve15. Lower tube16. Drain plug17. Snap ring18. Shuttle valve

1. Fork top boltIS. Spring seat2. Inner fork spring3. Inner fork tube4. Damper valve nut5. Damper valve6. Damper washer7. Damper tube

assembly8. Recoil spring

9. Inner fork tube endplug

10. Seal for screw (15)11. Dust cover12. Oilseal13. Outer fork tube14. Oil drain plug15. Damper tube holding

screw

spring (Fig. TM4-14). On models withexternal spring (Fig. TM4-15 or Fig.TM4-17), each unit contains 190cc ofoil. The late type fork (Fig. TM4-18)used on TR7V and T140V modelsshould contain 200cc of AutomaticTransmission Fluid (ATF). Recom-mended oil for earlier models is SAE 50oil above 90°F. SAE 30 at temperaturesfrom 60°F. to 90°F., and SAE 20 oilbelow 6O''F. Oil should be drained andfilled with correct type at least every6000 miles. Oil is drained by removingplugs at the bottom of fork lower(sliding) tubes. Forks are filled throughthe hole in top after removing plug (1—Fig. TM4-14, Fig. TM4-15, Fig. TM4-17orFig.TM4-18).

Disassembly and reassembly of lateforks is more easily accomplished usingthe special tool shown in Fig. TM4-18A. The tool holds the damper tubeassembly (7—Fig. TM3-18) while re-moving or installing the Allew screw(14). A 13/16 inch socket with a longextension can be used to hold nut (4) ina similar way if the special tool is notavailable. Coat threads of spring seat(lA) with "Permatex Super 300"; "Loc-tite Hydraulic Sealant" or equivalentto prevent leakage.

Rear suspension units are sealed andmust be renewed if leaking or dam-aged.

REPAIRSCYLINDER HEAD AND VALVES.

To remove the cylinder head, removethe fuel tank, coils, top engine supports(stays), rocker caps and rocker arm oilline. On 650cc models, loosen all ninecylinder head screws, remove the fivestud nuts and two screws attachingrocker boxes to cylinder head and liftoff the rocker boxes. On 750cc models,remove the attaching screws and studnuts, then remove the rocker hoses. Onall models, lift out the push rods andmark for correct assembly in the samelocation. Remove the exhaust pipes. On650cc models, remove the five re-maining cylinder head retainingscrews and lift the cylinder head off.

NOTE: The four cylinder headscrews which also attach the rockerboxes are already removed. On 750ccmodels, remove the ten cylinder headretaining screws and stud nuts. NOTE:Special threaded nuts are used at loca-tions (3,4, 5 & 6—Fig. TM4-19A).

When the cylinder head is removed,it is necessary to renew the push rodtube oil seals. Refer to the followingspecification data:Rocker arm bore

(I.D.) 0.5002-0.5012 in.Rocker shaft (O.D.) .. 0.4990-0.4995 in.

Fig. TM4-18A-A special tool is helpful for holdingthe damper tube while removing screw.

Valve stem to guide clearance—Inlet 0.0027-0.0032 in.Exhaust 0.0032-0.0047 in.

Valve seat and face angle .. 45 degreesValve seat width 3/32 in.Valve springs—type installed

6T Serial No. DUlOl and upInner-marked Red SpotOuter-marked Red Spot

TR6 Serial No. DU101.DU24874Inner-marked White SpotOuter-marked White Spot

TR6 Serial No. DU24875-DU66245Inner-marked Red SpotOuter-marked . Red Spot

TR6 Serial No. DU66246 and upInner-marked Red SpotOuter-Marked Green Spot

TR7VInner-marked Red SpotOuter-marked Green Spot

T120 Serial No. DU101-DU24874Inner-marked White SpotOuter-marked White Spot

T120 Serial No. DU24875-DU66245Inner-marked Red SpotOuter-marked Red Spot

T120 Serial No. DU66246 and upInner-marked Red SpotOuter-marked Green Spot

T140VInner-marked Red SpotOuter-marked Green Spot

Valve spring—specificationsInner-marked with red spot—

Free length 1 17/32 inchesNumber of coils 7y4

337


Fig. TM4-19-Cyiinder head retaining screws andstud nuts should be tightened in sequenceshown for 650cc models. Refer to Fig. TM4-19A

for 750CC modeis.

Inner-marked with white spot—Free length 1%Number of coils 7

Outer-marked with red spot—Free length 1% inchesNumber of coils 5̂ 2

Outer-marked with white spot—Free length 2 1/32 inchesNumber of coils 6V2

When reassembling, renew the pushrod tube oil seals and carefully positionthe cylinder head making certain thatpush rod tubes are correctly centered.On 650cc models, start the cylinderhead screws (1, 6, 7, 8 & 9—Fig. TM4-19) and install push rods. On 750ccmodels, install and tighten all ten cyl-inder head retaining nuts and screws(Fig. TM4-19A), Turn the crankshaftuntil both inlet push rods are at bottomof travel, then install the rear rockerbox and rocker arms assembly, NOTE:Be sure to install the three stud nuts onbottom before installing the screws andstud nuts on top. Turn the crankshaftuntil both front (exhaust) push rods areat bottom of travel, then install thefront rocker box and rocker arms as-sembly.

On 650cc models, the rocker armshaft nuts should be tightened to 22Ft,-Lbs. (3.0 kg-m) torque. Rocker boxretaining screw and stud nuts whichare V4 inch size should be tightened to 5Ft-Lbs. (0.7 kg-m) torque. The ninecylinder head retaining screws andstud nuts should be tightened in thesequence shown in Fig. TM4-19, Finaltorque for the 5/16 inch diameterscrews (Fig. TM 4-19) should be 15 Ft.-Lbs. and 25 Ft.-Lbs. for the % inchdiameter screws.

On 750cc models, the 5/16 inch cyl-inder head retaining nuts (1 & 2—Fig.TM4-19A) should be tightened to atorque of 16 Ft.-Lbs. (2.21 kg-m).Tighten the other cylinder head re-

Fig. TM4-19A-Cylinder head retaining screwsand stud nuts shouid be tightened in sequenceshown for 750cc models. Speciai nuts are usedat iocations (3, 4, 5 A 6) which accept rocker box

screws.

tain ing stud nuts and screws (% inchsize) to 18 Ft.-Lbs. (2.49 kg-m) torque.Tighten cylinder head retaining hard-ware evenly and slowly. The V4 inchsize rocker box screws should be tight-ened to 5 Ft.-Lbs. (0.7 kg-m) torque andthe 5/16 inch screws to 10 Ft.-Lbs. (1.38kg-m). Torque the rocker splindledomed nuts to 22 Ft.-Lbs. (3.0 kg-m).

On all models, refer to the VALVESYSTEM paragraphs in the Mainte-nance section for setting valve clear-ance.

PISTONS. RINGS AND CYLIN-DERS. Pistons and rings are availablein standard size and oversizes. Nom-inal bore size is 71mm (2.795 inches)for 650cc models, 75mm (2.953 inches)for early 750cc models, 76mm (2.992inches) for late 750cc models.

Piston Skirt Clearance—6T (Serial No. DUIOI-

DU5824) 0,0033-0.0043 inch0.084-0,109mm

6T (Serial No, DU5825-DU44393) , , , . 0.0016-0.0027 inch

0.041-0.069mmTR6 (Serial No. DUIOI-

DU44393) , . , . 0.0033-0.0043 inch0.084-0.109mm

TR6 (Serial No. DU44394 and upexcept 11:1 Compressionratio) 0.0046-0.0061 inch

0.117-0.155mmTR6 and T120 (Serial No. DU44394

and up with 11:1 Compressionratio) 0.0070-0.0084 inch

0.178-0.213mmT120TT (Before Serial No. DU44393

with 11:1 Compressionratio) 0.0073-0.0083 inch

0.185-0.211mmT120 (Serial No. DU44394 and up

except 11:1 Compressionratio) 0.0046-0.0061 inch

0.117-0.155mm

8.5:1 7.5 1Fig. TM4-20-Triumph pistons can be identifiedby measuring from center of piston pin bore. Pis-

tons shown are for 650cc models.

A. 1.416-1.424 inchesB. 1.488-1.492 inches

C. 1.498-1.r)02 inchesD. 1.845-1.849 inches

A. Locking holeB. Oil holeC. Cutaway1. Cam follower guide

block2. "C'ring3. Cam followers

Fig. TM4-21-On models after serial numberDU24874, the exhaust cam followers are pres-sure lubricated and must be Installed with cut'

away areas (C) toward outside as shown,

T120 (Before Serial No. DU44394except 11:1 Compressionratio) 0.0038-0.0048 inch

0.097-0.122mmTR7V and T14DV (All 750cc

models) 0.0036-0.0042 inch0.091-0.107mm

Maximum cylinder bore taperor out of round 0,005 inch

0.127mmRing side clearance in grooves(650cc)—

Compression rings 0.001-0.003 inch0.025-0.076mm

Oil control 0.0005-0.0025 inch0.013-0.064mm

Ring side clearance in groove (750cc)—Compression

rings 0.0015-0.0035 inch0.0038-0.089mm

Oil control 0.0015-0,0025 inch0.038-0.063mm

Ring end gap (650cc)—All rings 0,010-0,014 inch

0.25-0.36mm

338


Fig. TM4-22-On later 650ccmodels, make certain holein cylinder base gasket isover oil passages (A) incrankcase and (B) in cyl-

inder.

Fig. TM4-23-Make certainthat the two screws (S) areremoved when separating

crankcase halves.

Ring end gap (750cc)—Compression rings 0.008-0.013 inch

0.20-0.33mmOil control 0.010-0.040 inch

0.025-1.02mmWhen removing or installing the cyl-

inder, a shock absorber mountingrubber or similar rubber block shouldbe wedged between both sets of cam fol-lowers. If cam followers are not held in

position, they may fall into the crank-case. On models after serial numberDU24874, the exhaust cam followersare pressure lubricated. If the exhaustcam follower block is removed, makecertain that "0" ring (2—Fig. TM4-21)is positioned around guide block andlocking hole (A) is aligned with lockscrew hole before pressing into cyl-inder. Exhaust cam followers (3)

29

12 11 26 25

Fig. TM4-24-Exploded view of the crankshaft and camshafts. Nuts (15 B, 20) are left hand thread.

should be installed with cut-away faces(C) toward outside. Inlet cam followerblock on late models and both guideblocks on earlier models should be sim-ilarly pressed into place; however,these are not pressure lubricated anddo not have oil holes (B) or cut awaysections (C). On late models, make cer-tain that the cylinder base gasket isinstalled with hole in gasket over theoil passage (A—Fig. TM4-22) in crank-case and oil passage (B) in cylinder.

When installing piston rings on allmodels, make certain that side of thetwo compression rings marked "TOP"is toward top of piston. The cylinderretaining nuts should be tightened to35 Ft.-Lbs, torque.

CRANKSHAFT, CONNECTINGRODS AND CAMSHAFTS. To re-move the crankshaft or connectingrods, it is necessary to separate thecrankcase halves.

Remove the cylinder head, cylinder,ignition base plate, ignition cam,timing gear cover, oil pump and cam-shaft and crankshaft gears. NOTE: Thenuts attaching gear to camshaft areleft hand thread. Remove the clutch,alternator (stator and rotor), primarydrive sprockets, primary drive chain,gear box cover and transmission gears.Remove engine from the frame andremove the remaining screws and studnuts joining the crankcase halves.NOTE: Two screws are located at (S—Fig. TM4-23). Connecting rod crankpinstandard diameter is 1.6235-1.6240inches (41.237-41.25mm). Bearing in-serts are available in standard size aswell as undersizes.

1, Rotor retaining nut2, Tab washer3, Rotor4, Primary drive

sprocket5, Spacer6, Rod bearing inserts7, Oil tube8, Plug9, Screw (3 used)

10, Flywheel11, Crankshaft gear12, Nut13, Bushing14, Idler gear15, Nut16, Camshaft gear18. Exhaust camshaft19. Tachometer drive20. Oil pump drive nut21. Camshaft gear22. Inlet camshaft23. Spring24. Rotary breather

valve25. Ballbearing26. Washer27. Roller bearing28. DoweKEnergy

transfer ignitiononly)

29. Key (all exceptenergy transferignition)

30. Oil seal

339

Triumph 650 & 750 Twins

TM4-25-Camshaft timing marks must becorrectiy aligned as described in text.

The crankshaft left (drive) side mainbearing should be of the roller type. Onmodels before serial number DU13375,early type bearing can be changed tothe late roller type without changingany other parts. On models betweenserial number DU13375 and DU24874,the late type roller bearing can be in-stalled after installing the late typecrankshaft timing gear (11—Fig. TM4-24) and washer (26).

When assembling, the projectingtabs on connecting rod bearing insertsshould be on same side. The connectingrod nuts should be tightened to thetorque. Two types of connecting rodnuts have been used. The early typehas a machined finish and should betightened to 28 Ft.-Lbs. torque (3.87kg-m). The later, preferred nuts have adull grey finish for identification andshould be tightened to 22 Ft.-Lbs. (3.04kg-m) torque. The nuts are self lockingbut the manufacturer also suggestedusing "Loctite" to prevent loosening.

The three flywheel retaining screws(9—Fig. TM4-24) should be tightenedto 33 Ft.-Lbs. (4.6 kg-m) torque. Makecertain that the mating surfaces ofcrankcase halves are clean and smooth.Seal (30) should be installed from in-side after removing the roller bearingouter rod. Closed side of seal should betoward main bearings (27). To removeor install main bearings (25 & 27) fromcrankcase bores, the crankcases shouldbe heated to approximately 100° C.(212° F.).

When installing camshaft timinggears, install gears on shafts using thekeyway nearest the correct timingmark on gear. Several different gearshave been used, but marks are similar.Early camshaft gears have only onemark and are not interchangable. Lategears have two marks. The "A" mark(Fig. TM4-25) should be used for theexhaust camshaft and the "B" mark forthe inlet camshaft. Install the idlergear last making sure that marks arealigned correctly. The slot on crank-shaft gear should be between the two

19

iVIOTORCYCLE

3 2 1

20 18 7 6 5Fig. Tf^4-27-Exploded view of the clutch assembly. Refer to Fig. TM3-2B for installation of rubber

cushions (11 & 12).

1. Spring nuts2. Springs3. Spring cups4. Adjusting screw5. Pressure plate6. Driven plate

long dashes on idler gear as shown at(C). Align the correct dot (A) on ex-haust camshaft gear with dot on idlergear. On 6T models, align the correctdot (B) on inlet camshaft gear withshort dash (S). On all other models.

7. Friction disc8. Nut9. Washer

10. Outer cover11. Rebound rubber

cushion (small)

12. Drive rubber cushion(large)

13. Spider14. Clutch hub15. Inner cover

16. Spring screws* 17. Clutch drum

18. Thrust washer19. Rollers (20 used)20. Drive hub

12 11 13 14

align inlet camshaft dot (B) with thelong dash (L) on idler gear.

CLUTCH. Clutch plates can be re-moved after removing the primarychain case cover and the spring ad-justing nuts (1—Fig. TM4-27). Six fric-tion discs (7) and six driven plates (6)are used on all models. To remove theclutch drum and primary chain, it isnecessary to remove the alternatorrotor and stator, then use specialpullers to remove crankshaft primarydrive sprocket, clutch drum and pri-mary chain. When removing the clutchdrum (17), the special puller which at-taches to the drive hub (20) should beused.

When assembling the shock absorbercushions (11 & 12 Fig. TM4-28), usesoap to lubricate rubber cushions andmake certain that drive and reboundcushions are on the correct sides ofspider (13) as shown. NOTE: Do not useoil or grease to lubricate rubber cush-

Fig. TM4'2B-Ctutch cushions should be installadas shown. Use soap if necessary whan installing,

but do not use oil or grease.

11. Rebound cushion(sniall)

12. Drive cushion (large)

1. Gear shift pedal shaft2. Clutch release plunger3. Kick starter shaft

Fig. TM4'29^lew of gear box outer cover. Refer to Fig. TM4'30 for exploded view of tha oparatingassemblies.

340


Fig. TM4-30-Exploded view of parts located in the gear box outer cover. Refer to Fig. TM4-29 forassembled view.

1. Gear shift pedal shaft2. Clutch release

plunger3. Kick starter shaft4. Guide plate5. Ratchet pawls (2

used t

6. Ratchet springs (2used*

7. Pedal return springsH. Bushing9. "C'ring

10. Gear shift pedal

11. Connecting link(Before serial numberDU66246)

12. Clutch lever13. Balls(3used—-Hiin.)14. Camplate

15. Spring16. Washer17 Cotter pin18. Kick starter gear19. Return spring20. Bushing21. Kick starter pedal

Fig. TM4-32-Vlew of the gearbox Inner cover Installed.Refer to text for removal

procedure.

Ftg. TM4-33-When removingor Installing transmissiongears, be careful not to losethrust washer (10) or rotters

(2).

ions. "Loctite" should be used onthreads of the three screws attachingouter cover (10—Fig. TM4-27) to thehuh (14). Install spacer (5—Fig. TM4-24) with tapered side toward mainhearing. Position the crankshaft pri-mary drive sprocket, chain and clutchdrum (17—Fig. TM4-27) on shafts atthe same time. Washer (9) should heinstalled with cupped side out towardnut. On models after serial numherDU48144, nut (8) is self locking. Onearlier models, lock washer should heinstalled hetween washer (9) and nut(8) with the long tah engaging hole inspider (13). On all models, nut (8)should he tightened to 50 Ft.-Lhs.(6.9kg-m) torque. On early models,with lock washer, washer should bebent around nut after tightening. Referto ignition and electrical section wheninstalling the alternator rotor andstator. Refer to the primary drive chainparagraphs for adjusting chain tension.

FOUR SPEED GEAR BOX. Toremove the gear box outer cover, re-move the exhaust pipe and foot restfrom the right side. Loosen clutch cableadjuster and disconnect cable from theactuating spoke. Drain gear hox andengage fourth gear. Remove the twonuts and four screws attaching outercover, then remove the outer cover.Clutch operating cam, kick starter andgear change ratchet (Fig. TM4-29), areremoved with the outer cover.

To remove the inner cover, bend thetah washer back and remove nut (5—Fig. TM4-32), then lift off the kickstarter ratchet assembly. Unbolt andremove the right rear engine mountingplate. Remove nut (4) and withdrawthe detent plunger and spring. Removethe primary chain cover, alternatorassembly, primary chain, crankshaftsprocket and the complete clutch as-sembly. On models before serialnumber DU24875, disconnect thespeedometer cable. Remove the threescrews (1, 2 & 3) and remove the innercover. Remove the shift fork rail thenlift out the transmission gears andshafts as shown in Fig. TM4-33. Thetransmission output shaft and fourthgear (4—Fig. TM4-34) can be bumpedout of bearing after the output sprocket(28) is removed.

If needle bearings (11 or 12) are re-newed, bearings should be installed asshown in Fig. TM4-35 using a specialdrift. Bearing (12—Fig. TM4-34) isclosed on outside end, bearing (11) isopen. When removing and installingbearings (11, 12, 14 & 25), the appro-priate case should be heated to 100° C(212° F.). Oil seal (27) should be in-stalled with open side toward thebearing (25) and against snap ring (26).

341


25 26 27 29 30

10 13 6 10 12Fig. TM4-34-Exploded view of four speed transmission assembly. Refer to Fig. TM4-33 for assem-

bled view.

Input shuft(mainshafl)arvd first

8. SlidinggearOrd)9 Counter shaa

(layshafl) and drivegear

10. Thrust washers11. Needle bearing

(open)12. Needle bearing

(closed end)

gear2. Sliding gear (2nd)3, Sliding gear (3rd)4, Output shaft and

fourth gear5. Bushing6 First gear7. Sliding gear (2nd)

Bushing (5) should be pressed intoshaft (4) with oil groove toward teethon shaft. Bushing should protrude7/16-inch and must be reamed afterinstallation to provide 0.0032-0.0047inch clearance on input shaft (1). Firstgear bushing (13) should have 0.0025-0.0045 inch clearance on counter shaft(9).

When assembling, observe the fol-lowing: Install the cam plate (C—Fig.TM4-36) and detent plunger (D), springand nut (N), Turn the camplate untilthe notch between second and thirdgears engages detent plunger as shownin Fig. TM4-36. Use grease to stick the

13. First gear bushing14. Ball bearing15. Snap ring16. Clutch rod bushing17. Clutch rod18. Washer19. Sleeve20. Ratchet spring21. Kick starter gear

22. Ratchet23. Tab washer24. Nut25. Output shaft bearing26. Snap ring27. Oil seal28 Output sprocket29. Lock washer30. Nut

thrust washer (10) in position withgrooved side out as shown. Stick therollers (2—Fig. TM4-33) onto forkswith grease. Slide the assembled shaftsinto housing while carefully slidinggears as required to align rollers (2)with grooves in cam plate (C). NOTE:Be careful not to move the camplatewhen assembling. With parts correctlypositioned in housing, slide the shiftrail through shift forks with shoul-dered end (S) toward inside. Use greaseto stick thrust washer (10) aroundbearing (11—Fig. TM4-34) in the innercover with the grooved side towardgear (6). Coat mating surfaces of inner

Fig. TM4-37'The kick starter return springshould be installed on spline shown,

cover and gear case with sealer, alignthe center tooth of the gear selectorquadrant with center line of transmis-sion input shaft as shown at (A—Fig.TM4-32) and install the inner cover.Install the gear box outer cover tempo-rarily and check for correct shifting.NOTE: If gears can not be shifted cor-rectly, remove the covers and checkposition of camplate (C—Fig. TM4-36)and quadrant (A—Fig. TM4-32). In-stall the kickstarter ratchet assembly(18 through 23—Fig. TM4-34) over endof shaft and tighten nut (24) 45 Ft.-Lbs.torque. NOTE: Sleeve (19) may becrushed if nut (24) is over tightened.

When assembling the gear box outercover, refer to Figs. TM4-29 and TM4-30. The kick starter return springshould be installed with inner end ofspring over the spline shown at (L—Fig. TM4-37). Refer to appropriateparagraphs when assembling theclutch and the alternator assemblies.The table on the following page listsdetails of various transmission partsused in four speed transmission. Referto Figs. TM4-45, TM4-46, TM4-47,TM4-48 and TM4-49 for explanation ofstepped and non-stepped (parallel)shafts; shaved and non-shaft gears;

Fig. TM4-36-When assem-bllng four speed transmis-sion, detent plunger (D)should engage notch be-tween 2nd and 3rd gearsand the camptate (C) as

shown.

////////////AFig. TM4-3S-tf needle bearings (11 and 12-Fig.TM4-34) are removed, bearings should be In-stalled using a special drift. The bearings should

project 0,073-0.076 inch (C) Into the housing.

A. VA inches B. U/16inch C. 0.073-0.078 inch

342


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0-938& in. i0-0980 in j

NON-STEPPED MAINSHAFT

STEPPED MAINSHAFT

Fig. TM4-45-Vlews of fourspeed transmission inputshafts (mainshafts} showingdifferences between non-stepped and stepped types.

0 9945tn.0 9940 in.

0 9985 in. ̂0 9980 in.

NON «* STEPPED tAYSHAFT

STEPPED tAYSHAFT

Fig. TM4-46-Views of fourspeed countershafts (lay-shafts) showing differencesbetween stepped and non-

stepped types.

Fig. TM4-47''Views showingdifferences between un-

shaved and shaved gears.

UNSHAVEDOEAR

small and large splined gears. Alsolisted are the dates when used in orig-inal production. Some of the improve-ments incorporated in later productioncan be installed in earlier transmis-sions; however, it is extremely impor-tant to select the correct combinationto ensure proper operation. Small boregears should never be installed on anon-stepped shaft and large bore gearsshould never be used on a stepped

OEAR

shaft. Mainshafts have two differenttypes of threads (C.E.L or U.N.F.). Besure that the nuts and spacers are cor-rect for the shaft used as well as thegears used. Installing late mainshafthigh gears in early transmission maynecessitate installing later plate andseal at rear of clutch. The gearboxcasting must be modified to changelayshaft (countershaft) from plainbushing to needle roller type.

LAYSHAFT 3rd Gf AR

8IMALI 8ORE1-1230 in.1-12t5 in.

Fig. TM4-48~Cross section drawing of mainshaftsecond gear with bore diameters for iarge bore

and smaii bore types.

MAMSHAFT 2nd PC AH

Fig. TM4'49-Cross section drawing of layshaftthird gear with bore diameters for targe bore

and small bore types.

FIVE SPEED GEAR BOX. Toremove the gear box outer cover, re-move right side exhaust pipe and footrest. Loosen the clutch cable adjusterand disconnect cable at the hand lever.Remove plug from cover and releasethe cable from actuating arm. Discon-nect cable and housing from gearboxouter cover. Drain gear box and engagefifth gear. Remove the two nuts andfour screws that attach cover, thendepress kickstarter slightly and re-move cover. The clutch operating cam,kick starter and gear change ratchetare removed with cover.

To remove the inner cover, unboltand remove the right rear enginemoimting plate. Bend tangs of lockwasher down and remove nut (24—Fig.TM4-52). Remove the three screws (3)and remove cover from dowels.

Remainder of disassembly will de-pend upon work done. The completeclutch assembly must be removed be-fore input shaft (1—Fig. TM4-50) canbe removed. The transmission outputsprocket (28) must be removed beforeoutput shaft (4) can be removed.

The gearbox or cover should beheated to approximately 100°C. whenremoving or installing bearings. Referto Fig. TM4-35 for installing counter-shaft (layshaft) needle bearings. Thebronze thrust washers on the counter-shaft should be positioned with grooved

344


28 29 30

16 1

V17

24 23 22 21 20 19 18 15 14 8 3B 3 2

Fig. TMA-St-Drawing of transmission showingpositions of shift cam and shift fori(s in neutral.

11 12 8B 6 7 7B 9 10Fig. TM4-50-Expioded view of five speed transmission gears and associated parts.

1. Input shaft(mainshafl)

2. Fourth gear3. Third gear

3B. Bushing4. Output shafl and

fifth gear5. Needle roller

bearings5S. Oilseal

6. First gear6B, Bushing

7. Second gear8. First and second gear9. Third gear

10. Countershaft(layshaft) with fourthgear and drive gear

11. First gear drive dog

surfaces toward gear on shaft (10—Fig.TM4-50) and first gear drive dog (11).

Assemble transmission gears, shafts,shift forks and shift cam with parts in

12. Snap ring14. Ballbearing15. Snap ring16. Clutch rod bushing17. Clutch rod18. Washer19. Sleeve20. Ratchet spring21. Kick starter gear

22. Ratchet23. Tab washer24. Nut25. Output shaft roller

bearing26. Snap ring27. Oilseal28. Output sprocket29. Lock washer30. Nut

Fig. TM4-52-Drawing of inner cover showing thethree screws (3) which attach cover.

first gear. Install the cover with the topof the second tooth on quadrant alignedwith center of foot change spindle boreas shown at (A—Fig. TM4-52).

Fig. TM4-53-The fourth speed gear and the drivegear are pressed onto the countershaft (iay-shaft). Distance (D) must be 0.653-0.655 inch(t6.58-16.64mm} and clearance between gears

shouid be at feast 0.007 inch (0.18mm).

345

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