Yamaha YT175J 1982 Service Manual Download Page 66

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Summary of Contents for YT175J 1982

Page 1: ...CONTENTS GENERAL INFORMATION PERIODIC INSPECTIONS AND ADJUSTMENTS ENGINE OVERHAUL CARBURETION CHASSIS ELECTRICAL APPENDICES ...

Page 2: ...ATION MACHINE IDENTIFICATION 1 1 Frame serial number 1 1 Engine serial number 1 1 SPECIAL TOOLS 1 2 For tune up 1 2 For engine service 1 2 For chassis service 1 3 For electrical components 1 4 Additional tools and supplies 1 4 ...

Page 3: ...ipe 1 Frame serial number NOTE ________________________ The first three digits of these numbers are for model identification the remaining digits are the unit production number Starting Serial Number YT175J 5V7 000101 1 1 Engine serial number The engine serial number is stamped into the elevated part of the right rear section of the engine ...

Page 4: ...1 Timing light 2 Tachometer For engine service 1 Dial gauge PIN 90890 03002 00 2 Dial gauge stand PIN 90890 01256 00 3 Dial gauge needle PIN 90890 03099 00 1 2 Tools 1 2 and 3 are use to set the ignition timing 4 Crankcase separation tool PIN 90890 01135 00 This tool is use to split the crankcase as well as remove the crankshaft from either case 5 Crank installer pot PIN 90890 01275 00 6 Crank ins...

Page 5: ...to 1 3 10 Flywheel holding tool PIN 90890 01235 00 Use this tool to hold the flywheel magneto while removing or tightening the flywheel magneto securing nut For chassis service 1 Steering nut wrench PIN 90890 01051 00 Use this wrench to put the proper tension on the steering head bearing 2 Front fork cylinder holder PIN 90890 01300 00 This tool is used to loosen and tighten the front fork cylinder...

Page 6: ...tool and supplies 1 Thickness gauge set 2 Torque wrench 3 Tire pressure gauge 4 Fluid mesuring cup 5 Micrometer 6 Slide caliper 7 Cylinder gauge 8 Magnetic stand 9 Grease gun 10 Yamalube 4 cycle oil 11 Yamalube 2 cycle oil 12 Yamabond 4 13 Yamaha chain and cable lube or SAE 10W30 motor oil 14 Medium weight wheel bearing grease 15 Locktit stud N bearing mount Red ...

Page 7: ...er release valve 2 6 Transmission oil 2 6 Checking ignition timing 2 7 CHASSIS 2 8 Air cleaner 2 8 Front brake shoe inspection 2 8 Rear brake pad inspection 2 8 Brake adjustment 2 9 Drive chain tension check 2 11 Drive chain tension adjustment 2 11 Drive chain cleaning and lubrication 2 11 Steering head adjustment 2 11 Wheel bearings 2 12 Fuel cock 2 13 Tires 2 13 Cable inspection and lubrication ...

Page 8: ...idity then all parts must be lubricated much more frequently that shown on the chart to avoid damage caused by water to metal parts PERIODIC MAINTENANCE Initial Thereafter every Item Remarks 1 3 6 6 1 Month Months Months Months Year Cylinder head Exhaust system Decarbonize 0 0 0 Spark arrester Spark plug Inspect Cleaning or replace as required 0 0 0 0 Air filter Wet type Must be washed and damped ...

Page 9: ... Apply lightly Lithium base grease 0 0 0 Brake cam shaft Apply lightly Lithium base grease 0 0 0 Drive chain Lubricate chain thoroughly Motor oil SAE 30 50 0 0 0 1 Month Front forks Drain completely check Yamaha fork oil10wt or 0 0 1 specifications SAE 10W30 type SE motor oil Year Steering bearings Inspect thoroughly pack Medium weight wheel bearing Check 2 moderately grease Years Wheel bearings D...

Page 10: ...II A loosen the three screws from over flow chamber and completely drain gasoline from the pipe II A and chamber Idle speed 1 Turn the pilot air screw until it lightly seats then back it out to specification This adjustment can be made with engine stopped 2 3 Air screw Turns out 1and 1 4 2 Start the engine and let it warm up 3 Throttle stop screw Turn throttle stop screw in or out to achieve smoot...

Page 11: ...tch mark 2 Pump cable 5 Guide pin 3 Adjust pulley 2 4 3 If the mark and pin are not in alignment loosen the cable length adjuster lock nut on top of crankcase cover and adjust cable length until alignment is achieved 4 Tighten adjuster lock nut 1 Cable adjuster 2 Lock nut Minimum pump stroke check and ad justment 1 While running the engine idle observe the pump adjust plate carefully and stop the ...

Page 12: ... the Autolube tank has run dry Whenever any portion of the Autolube system is disconnected If the machine lies on its side after falling over 2 5 1 Remove the pump cover and remove the bleed screw 1 Bleed screw 2 Keep the oil running out until air bubbles disappear NOTE _________________________ Check the bleed screw gasket and if damag ed replace with a new one 3 When air bubbles are expelled com...

Page 13: ...the engine has started and then goes off When the engine oil level is low The light keeps going on after the engine has started If the light bulb is burnt out The light will not come on after the engine has started Checking the water release valve Before starting off be sure to check that the valve is closed Before cleaning the air cleaner element check if there is impurities in the element case 2...

Page 14: ...ter marked on the crankcase and the marks on the flywheel magneto 1 Mark 2 Stationary pointer 3 Timing light 2 Remove the crankcase cover Ll 3 Connect the timing light to the spark plug lead wire 4 Start the engine and keep it running at the specified speed Use a tachometer for checking Specified engine speed 1 600 50 r min 2 7 5 While running the engine at the specified speed check to see that th...

Page 15: ...d fittings for an air tight seal Tighten all fittings thoroughly to avoid the possibility of un filtered air entering the engine 2 8 engine with the air cleaner element removed This will allow unfiltered air to enter causing rapid wear and possible engine damage Additionally operation without the cleaner element will affect car buretor jetting with subsequent poor performance and possible engine o...

Page 16: ... lever and brake shoe plate a Loosen the lock nut on the brake lever holder fully turn the adjuster in b Turn the adjuster on the shoe plate in or out until proper adjustment is achieved c Unless the shoe plate adjuster helps br ing a proper play turn to the lever holder adjuster d Tighten the lock nut 2 9 1 Adjuster 2 Lock nut 2 Brake pedal WARNING When adjusting the rear brake first ad just the ...

Page 17: ...g bolt Then tighten the adjusting bolt lock nut 1 Adjusting bolt 2 Lock nut Tightening torque 15 Nm 1 5 m kg 11 ft Ib 3 Rear brake lever WARNING Never adjust the brake lever without first adjusting the brake caliper and brake pedal 2 10 a Loosen the brake cable lock nuts and turn the adjuster so that the rear brake cable and brake caliper lever have no play at all After adjusting tighten the lock ...

Page 18: ... Drive chain cleaning and lubrication This machine has a drive chain with small rubber O rings between the chain plates Steam cleaning high pressure washes and certain solvent can damage these O rings Use only kerosene to clean the drive chain Wipe it dry and thoroughly lubricate it with SAE 30 50 motor oil Do not use any other lubricants on the drive chain They may con tain solvents that could da...

Page 19: ...rder Tightening torque Steering stem nut 65 Nm 6 5 m kg 47 ft lb Cap bolt 54 Nm 5 4 m kg 39 ft Ib Handlebar holder bolt 34 Nm 3 4 m kg 24 5 ft Ib 1 Handlebar holder bolt 2 Steering stem nut 3 Cap bolt 2 12 6 Recheck steering adjustment to make sure there is no binding when the forks are moved from lock to lock If necessary repeat the adjustment pro cedure Wheel bearings If a rolling rumble is noti...

Page 20: ...faces are scratched or corrod ed the fuel cock assembly must be replaced If there is abrasive damage to any components the fuel tank must be drained and flushed 5 Reassemble the fuel cock and install it on the fuel tank Tires This model is equipped with low pressure tires Pay attention to the following points Recommended tire pressure 14 7 kPa 0 15 kg cm2 2 2 psi Vehicle load limit 100 kg 220 Ib T...

Page 21: ...itions Standard tire circumference 1 735mm 68 3 in Minimum tire circumference 1 725mm 67 9 in Cable inspection and lubrication 1 Damage to the outer housing of the various cables may cause corrosion Often free movement will be obstructed An unsafe condition may result Replace such cables as soon as possible 2 If the inner cables do not operate smoothly lubricate or replace them Recommended lubrica...

Page 22: ... a new bulb into position and secure it with the bulb holder 4 Reinstall the light unit assembly to the headlight body Adjust the headlight beam if necessary 5 Reinstall the front panel Headlight beam adjustment When necessary adjust the headlight beam asfollows 1 Remove the front panel 2 Adjust vertically by moving the headlight body 3 Reinstall the front panel 2 15 ...

Page 23: ...n and piston 3 4 Crankcase cover right 3 4 Clutch assembly and primary drive gear 3 4 Change shaft assembly 3 6 Drive sprocket 3 6 Crankcase 3 6 Transmission and shifter 3 6 Crankshaft 3 7 INSPECTION AND REPAIR 3 7 Cylinder head 3 7 Cylinder 3 7 j iston pin and bearing 3 8 Piston 3 8 Piston rings 3 9 Autolube pump 3 9 Starter 3 10 Clutch 3 11 Primary drive 3 14 Change shaft and change levers 3 14 ...

Page 24: ... 16 Crankshaft installation 3 16 Transmission and shifter installation 3 17 Crankcase 3 19 Change shaft assembly 3 19 Primary drive gear and clutch assembly 3 19 Crankcase cover right 3 19 Piston 3 19 Cylinder 3 20 Cylinder head 3 20 Reed valve 3 20 MOUNTING 3 21 ...

Page 25: ...ion oil Before beginning of the servicing fully cool the engine down Exhaust 1 Remove the seat and rear fender 2 Remove the side cover assembly 3 Remove exhaust pipe assembly 3 1 Wiring and cables 1 Remove the spark plug cap oil pump cover pump cable and oil pipe 1 Clip NOTE ______ Do not leave the oil pipe disconnected from the oil pump or oil will flow out of the oil tank It is advisable to plug...

Page 26: ...buretor 2 Remove the carburetor Flywheel magneto 1 Remove the starter assembly 2 Remove the starter pulley 3 2 3 Remove the flywheel securing nut use Flywheel holding tool 1 Flywheel holding tool 4 Install flywheel puller on flywheel and tighten it NOTE ____________ The puller body has lefthand thread 5 While holding puller body tighten push bolt This will pull flywheel off the tapered end of the ...

Page 27: ...l 1 Remove the engine mounting bolts and remove engine from right side of frame 3 3 LIGHTING COIL FLYWHEEL MAGNETO ENGINE DISASSEMBLY Reed valve assembly 1 Remove reed valve assembly holding bolts 4 carburetor joint and reed valve assembly Cylinder head and cylinder 1 Remove the cylinder head holding nuts cylinder head and head gasket ...

Page 28: ...ill not ac cidentally drop the clip into the crankcase 2 Remove the piston pin using the piston pin puller Crankcase cover right 1 Remove the shifter cover 2 Remove the guide from crankcase cover 3 4 1 Shift guide 2 Ball holder 3 Compression spring 4 Guide 3 Remove right crankcase cover screws and cover The cover can be removed without removing the Autolube pump Clutch assembly and primary drive g...

Page 29: ...tween the tooth of the primary drive gear and primary driven gear to lock them and loosen the primary drive gear lock nut PRESSURE PLATE 2 PRESSURE PLATE 3 3 5 4 Using the Flywheel holding tool remove the nut and washer Remove the clutch boss and driven gear clutch housing 1 Flywheel holding tool ...

Page 30: ...rew may be backed out slightly to level tool body Use a soft hammer to tap on the case half Tap only on reinforced portions of case Do not tap on gasket mating sur face Work slowly and carefully Make sure the case halves separate evenly If one end hangs up take pressure off the push screw realign and start over If the halves are reluctant to separate check for a remaining case screw or fit ting Do...

Page 31: ...by re surfacing as follows Place 400 600 grit wet sandpaper on surface plate and re surface head using a figure eight sanding pattern Rotate head several times to avoid removing too much material from one side Cylinder 1 Hone cylinder bore using a hone with fine stones Hone no more than required to remove all wear marks 2 Using a Cylinder Gauge set to standard bore size measure the cylinder Measur...

Page 32: ... 3 8 Piston 1 Remove carbon deposit from ring grooves using old piston ring as shown 2 Using an outside micrometer measure piston diameter The piston is camground and tapered The only measuring point is at right angles to the piston pin holes about 10 mm 0 39 in from bottom of piston Compare piston diameter to cylinder bore measure ments Piston maximum diameter as shown below subtracted from minim...

Page 33: ...fac tory setting This situation is however extremely rare If output is suspected check the following 1 Obstructions in delivery line to pump or from pump to cylinder 2 Worn or damaged pump body seal or crankcase cover seal 3 Missing or improperly installed check ball or spring 4 Improperly installed or routed oil delivery line s 5 Loose fitting s allowing air to enter pump and or engine b If all i...

Page 34: ... the spring in the wrong way 3 Hook the loop on the outer end of the spring onto the spring hook in the starter case Then thoroughly grease the spr ing 3 10 STARTER ROPE 2 Insert the rope end to the hole in the shave drum and knot on the rope end Wind the rope around the shave drum in the direction of the arrow and hook the rope in the cut on the shave drum periphery 370 mm 14 6 in from the end of...

Page 35: ...g washer and nut Tightening torque 10 Nm 1 0 m kg 7 2 ft lb 1 Drive plate spring 2 Drive pawl NOTE ____________________ Make sure the drive pawl drive plate spring and drive plate are installed in the correct way 3 11 5 After the completion of assembly check the starter for smooth operation Pull out the starter rope about 80 130 mm 3 5 in and make sure that the starter pawl moves out of the drive ...

Page 36: ...s and check fric tion plates clutch hub and colar THICKNESS 1 6mm 10 063 in 3 12 3 Clutch adjustment Measure the gap between the friction plate and pressure plate with a thickness gauge If the gap is found incorrect it should be properly adjusted by changing the thickness of the clutch plate Thickness 1 2 mm 0 047 in 1 4 mm 0 055 in or 1 6 mm 0 063 in Clutch adjustment gap Place the 1 6 mm 0 063 i...

Page 37: ...clutch plates may burn 7 Thoroughly clean the primary driven gear assembly and spacer Apply a light film of oil on the bushing surface and spacer Fit the spacer into the bushing It should be a smooth thumb press fit The spacer should rotate smoothly within the bushing 8 Check splines on clutch boss for signs of galling If moderate deburr If severe replace NOTE ________________________ Galling on e...

Page 38: ...the guide bars across a surface plate If any bar is bent replace 3 Check the shift cam grooves for signs of wear or damage If any profile has ex cessive wear and or any damage replace cam 4 Check the cam followers on each shift fork for wear The follower should fit snugly into its seat in the shift fork but should not be overly tight Check the ends that ride in the grooves in the shift cam If they...

Page 39: ..._______ Bearing s are most easily removed or in stalled if the cases are first heated to approx imately 90 120 C 194 248 F Bring the case up to proper temperature slowly Use an oven 2 Check oil seal lips for damage wear Replace as required 3 Always replace crankshaft oil seals whenever the crankshaft is removed 4 Installation In tall bearing s and oil seal s with their manufacture marks or numbers...

Page 40: ...long the bolt or nut flat s after the bolt or nut has been properly tightened LOCK WASHER OR LOCK PLATE Bearings and oil seals 3 16 1 Install the bearing s and oil seal s with their manufacturer s marks or numbers facing outward In other words the stamped letters must be on the side ex posed to view When installing oil seal s apply a light coating of light weight lithium base grease to the seal li...

Page 41: ... move freely and that all loose shims are in place Make sure all shafts are fully seated MAIN AXLE 1ST WHEEL oo d 5TH WHEEL i1l 3RD WHEEL O 4TH WHEEL t b J DOG CLUTCH OQIt2ND WH a rI1f J 0 VEAXL tI COLLOR Dcc6 DRIVE SPROCKET SHIFT FORK 1 1 SHIFT FORK 2 r SHIFT CAM 3 17 ...

Page 42: ...SMISSION ASSEMBLY 3RD 4TH PINION L ur tr 5TH POINT MAIN AXLE AI f t t 5TH WHEEL DRIVE AXLE 3RD WHEEL 1ST WHEEL GEAR RATIO 1st 35 10 3 500 2nd 31 14 2 214 3rd 28 18 1 555 4th 25 21 1 190 5th 23 23 1 000 3 18 ...

Page 43: ...ft lever 1 Adjusting screw 2 Lock nut Primary drive gear and clutch assembly 3 19 1 Install the primary drive gear onto the crankshaft Primary drive gear nut torque 55 Nm 5 5 m kg 40 ft Ib 2 Install the clutch assembly onto the main axle Clutch boss tightening torque 40 Nm 4 0 m kg 29 ft Ib When install the circlip be sure to locate it as illustration below 1 Circiip 2 Clutch housing Crankcase cov...

Page 44: ... torque 30 Nm 3 0 m kg 22 ft Ib Cylinder head stud bolt 25 Nm 2 5 m kg 18ft Ib Reed valve Install the reed valve assembly and car buretor NOTE ________________________ Bring the chamber in the cylinder reed valve housing to align with the 5 mm diameter hole in the reed valve body and the pipe joint at tached to the carburetor joint and tighten the reed valve assembly If these are out of alignment ...

Page 45: ... 22 5 ft Ib Rear upper 31 Nm 3 1 m kg 22 5 ft Ib Rear under 42 Nm 4 2 m kg 30 5ft lb Drive sprocket nut 55 Nm 5 5 m kg 40ft Ib Flywheel magnet 70 Nm 7 0m kg 50ft lb 3 Install the exhaust pipe assembly Use a new gasket 4 Install the side cover seat assembly 5 Add transmission oil Transmission oil capacity 0 8 0 9 L 0 7 0 8 Imp qt 0 8 1 0 US qt 10 Nm 10 1 m kg 0 7ft lb 3 21 ...

Page 46: ...CHAPTER 4 CARBURETION CARBURETOR 4 1 Specifications 4 2 Inspection 4 2 Adjustment 4 2 REED VALVE 4 4 Inspection 4 4 Water release valve 4 4 FUEL PUMP 4 5 Fuel pump inspection 4 5 ...

Page 47: ...CARBURETION CARBURETO R _ _ _ __ fI l I JET NEEDLE AIR SCREW ftlltiJO WASHER 4 1 ...

Page 48: ... Replace these components as a set 1 Aoat valve 2 Valve seat 4 Inspect the jet needle for bends or wear If the needle is bent or severely worn replace it 4 2 Adjustment 1 Float height a Reinstall components except for the flnat chamber Incline the carburetor until the float arm tang lightly contacts the float valve so th Jt the end of the float valve does not hang down of float weight and measure ...

Page 49: ...g slightly c Adjustment Check the float valve and valve seat for wear before adjustment Make the adjustment by bending the tang on the float arm 2 Jet needle If it is necessary to alter the mid range air fuel mixture characteristics of the machine the jet needle position may be changed Move the jet needle up for a leaner condition or toward the bottom position for a richer condition Jet needle typ...

Page 50: ...a 9 mm 0 35 in If it is 0 5 mm 0 020 in more or less than specified replace the valve stop per 4 Check reed valve for bending If beyond tolerance replace reed valve Reed valve bending limit 0 2 mm 0 008 in 5 During reassembly note the cut in the lower corner of the reed and stopper plate Use as aid to direction of reed in stallation 4 4 Water release valve Check the valve for good sealing or move ...

Page 51: ...L PIPE FUEL COCK NOTE ________________________ The fuel pump should not be disassembled If it malfunctions replace it with a new one Piping NOTE _______________________ Fuel pump installation as well as piping should be carried out in the correct manner For fuel pump installation and piping refer to the diagram given below FUEL PUMP PULSE PIPE TO CARBURETOR JOINT FUEL PIPE SPRING TO CARBURETOR 4 5...

Page 52: ...EEL 5 3 Removal 5 3 Rear wheel inspection 5 3 Replacing the wheel bearings 5 3 Checking the rear axle 5 4 Installing the rear axle 5 4 Installing the rear wheel 5 5 REAR BRAKE 5 6 Brake pad replacement 5 6 Brake inspection and repair 5 6 Brake assembly 5 7 FRONT FORK 5 9 Removal and disassembly 5 10 Inspection 5 11 Assembly 5 11 Installing the front fork 5 12 STEERING HEAD 5 13 Adjustment 5 14 Rem...

Page 53: ...DRIVE CHAIN AND SPROCKETS 5 15 Adjustment 5 15 Sprocket inspection 5 15 Removal 5 16 Assembly 5 16 Drive chain cleaning and lubrication 5 16 CABLE AND FITTINGS 5 17 Cable maintenance 5 17 ...

Page 54: ...n from the axle with emery cloth Place the axle on a surface plate and check for bent If bent replace the axle Do not attempt to straighten a bent 5 1 Front wheel inspection 1 Check for cracks bends or warpage of the wheels If a wheel is deformed or cracked it must be replaced 2 Check wheel runout If deflection exceeds tolerance below check the wheel bearing or replace wheel as required Rim runout...

Page 55: ...er race with a soft metal drift punch and hammer The spacer floats between the bear ings Both bearings can be removed in this manner WARNING Eye protection is recorn mended when using striking tools 3 To install the wheel bearing reverse the above sequence Use a socket that mat ches the outside diameter of the race of the bearing to drive in the bearing Do not strike the center race or balls of th...

Page 56: ...cle Apply the parking brake 5 3 2 Remove the cotter pins from the right and left rear wheel loosen the axle nuts and remove the tires 1 Cotter pin 2 Axle nut 3 Remove the pad case and chain case 4 Straighten the lock washer on the right side and loosen the ring nut and release the parking brake 1 Ring nut 2 Lock washer 5 Loosen the caliper holding nuts and remove the outer caliper and disc plate 1...

Page 57: ...d check for the rear axle at both ends 1 Rearaxle DIAL GAUGE Rear axle runout limit 1 5 mm 0 06 in 2 If the runout exceeds 1 5mm 0 06 in replace the rear axle with a new one Installing the rear axle Positioning the rear axle 1 Drive the rear axle into the rear hub NOTE ____________ The rear shaft is shaped symmetrical so that it can be inserted from either end 2 Install the drive chain Tightening ...

Page 58: ...t lb 6 Tighten the ring nut which is set in 4 above to specification Tightening torque 135 Nm 13 5 m kg 98 ft Ib 7 Bending the lock washers over the ring nuts on both ends of the rear axle NOTE ____________ Always use new lock washers 8 Tighten the caliper and install the pad case and chain case Tightening torque 39 Nm 3 9 m kg 28 ft Ib 5 5 9 Adjust the drive chain Refer to Drive chain adjustment ...

Page 59: ...e the parking brake to set the rear wheel free Loosen the caliper holding nuts and remove the outer caliper 5 6 1 Caliper holding nut 2 Outer caliper 5 Pull out the disk plate 2 Disc plate 6 Replace the inner and outer brake pads with new ones NOTE ____________ Replace the pads as a set if either one is worn to the specified limit I Wear limit 1 5 mm 0 06 in Brake inspection and repair 1 Replace t...

Page 60: ... Check for wear and deflection of the disc If the disc is worn beyond minimum thickness or if deflection ex ceeds thtl specified amount replace the disc Maximum deflection 0 5 mm 0 02 in Minimum disc thickness 3 mm 0 12 in DIAL GAUGE BRAKE DISK 1 Disc plate boss NOTE ____________ Avoid applying too much grease or it overflows to the disc plate thus causing brake slippage Therefore after greasing i...

Page 61: ...8ft Ib 1 Caliper holding nut 2 Outer caliper 4 Tighten the ring nut to specification and lock it with the lock washer NOTE Always use a new lock washer 5 Install the pad case 6 Adjust the brake For this adjustment refer to page 2 9 5 8 ...

Page 62: ...G I _ I I J EA IIIZ l r THER PIPE I j rr i fii I I I I o I I I I t d I I 1 i j j II O RINj i ____ STOPPER I RING ____ I SPRING I SEAT f 1 FORK I SPRING I DAMPER Rob I TAPER SPI DLE RETAINING CLIP FORK SEAL I I fj L_ Ii _ _____J ...

Page 63: ...of the each fork 5 ThE spring seat and fork spring are re tained by a stopper ring Spring wire circlip It is necessary to depress the spring seat and fork spring to remove the stopper ring Remove the stopper ring by carefully prying out one end with a small screwdriver 6 Remove the fork spring and drain the oil completely 7 Remove the cylinder securing bolt from the bottom of the fork assembly Hol...

Page 64: ...e spring seat If it s damaged replace it Assembly 1 Make sure all components are clean before assembly Always install a new fork seal Do not reuse a seal 2 Apply oil to the fork seal and install the fork seal by pressing it in with a large socket Install the retaining clip 3 Install the inner fork tube into the outer fork tube 4 Apply locktite Stud N Bearing Mount red to the cylinder securing bolt...

Page 65: ...be and reinstall the rubber cap 1 Be sure the stopper ring is properly seated in the groove in the fork tube 2 When installing the fork make sure the breather pipe is properly con nected and routed UNDER BRACKET BREATHER PIPE 2 Install the pinch bolts and tighten them to specification Tightening torque 54 Nm 5 4 m kg 39 ft Ib 3 Reinstall the front wheel Refer to Installing the front wheel on page ...

Page 66: ...ith front fork assembly Ball quantity Upper 22 pcs Lower 19 pcs 5 14 Inspection 1 Wash the bearing in solvent 2 Inspect the bearings for pitting or other damage Replace the bearings if pitted or damaged Replace the race when the balls are replaced 3 Clean and inspect the bearing races Spin the bearings by hand If the bear ings are not smooth in their operation replace balls and races Assembly 1 Gr...

Page 67: ... Nm 6 5 m kg 47 ft Ib Cap bolt 50 Nm 5 0 m kg 36 ft Ib Handle holder bolt 34 Nm 3 4 m kg 24 5 ft Ib 5 15 DRIVE CHAIN AND SPROCKETS Adjustment Refer to Drive chain adjustment on page 2 11 Sprocket inspection 1 Check sprocket wear Replace if tooth width has decreased as shown 1 1 4 tooth 2 Correct 3 Roller 4 Sprocket 2 Replace if tooth wear shows a pattern such as that in the illustration or similar...

Page 68: ... driven sprocket and chain together Assembly 5 16 1 Install the drive sprocket driven sprocket and drive chain together Torque the drive sprocket nut and ring nut to specification Bend a lock tab against a nut flat Drive sprocket nut 55 Nm 5 5 m kg 40 ft Ib Ring nut 135 Nm 13 5 m kg 98ft Ib 2 Install the chain case 3 Adjust the drive chain Refer to Drive chain adjustment on page 2 11 4 Install the...

Page 69: ...le routing is very important however For details of cable routing see the cable routing diagrams at the end ofthis manual 1 Remove the cable 2 Check for free movement of cable within its housing If movement is obstructed check for fraying or kinking of the cable strands If damage is evident replace the cable assembly 3 To lubricate cable hold in a vertical position Apply lubricant to uppermost end...

Page 70: ...IGNITION SYSTEM 6 1 Checking the magneto charge coil and pick up coil 6 2 Ignition timing 6 2 Spark gap test 6 2 Ignition coil resistance test 6 2 Spark plug 6 3 LIGHTING AND SIGNAL SYSTEMS 6 3 Lighting tests and checks 6 3 ...

Page 71: ...W R White Red O Orange B W Black White G Green G Y Green Yellow L Blue Y R Yellow Red Br Brown This circuit diagram shows the ignition circuit in the wiring diagram 0 0 1 UNrr OIL WARNING CHECKER rw IGNITION COIL 6 1 t OIL LEVEL GAUGE CHARGING COIL FLYWHEEL MAGNETO ...

Page 72: ...tion system will fire across a sufficient gap the engine ignition system can be considered good If not proceed with in dividual component tests until the problem is found 6 2 1 Warm up engine thoroughly so that all electrical components are at operating temperature 2 Stop engine and connect tester as shown 8EB rn H _ CD 1 Electro tester 2 Plug wire from coil 3 Spark plug 3 Start engine and increas...

Page 73: ...ug with a colder type for high speed riding NOTE ____________ First check for ignition timing and intake air leaks before changing spark plug types 2 Inspection Instruct the rider to a Inspect and clean the spark plug at least every 6 months b Clean the electrodes of carbon and ad just the electrode gap c Be sure to use the proper reach plug as a replacement to avoid overheating foul ing or piston...

Page 74: ...ire windings of the lighting coil a Switch Pocket Tester to x lQ position and zero meter b Connect positive test lead to Yellowl Red wire from magneto and negative test lead to good ground on engine Read the resistance on ohms I I L 1 Set the tester X 1Q position Lighting coil resistance 0 46Q 10 20 C 68 F Color Y R B 6 4 ...

Page 75: ...N TABLES 7 10 EXPLODED DIAGRAMS 7 11 CYLINDER HEAD CyLINDER 7 11 CRANKSHAFT CONNECTING ROD PiSTON 7 12 CRANKCASE 7 13 TRANSMISSION 7 14 CLUTCH 7 15 SHIFT CAM FORK 7 16 SHIFT SHAFT PEDAL 7 17 STEERING 7 18 FRONT FORK 7 19 FRONT WHEEL 7 20 REAR WHEEL 7 21 ELECTIRCAL 7 22 CABLE ROUTING 7 23 YT175J WIRING DIAGRAM ...

Page 76: ... induction Cylinder Arrangement Single cylinder Forward inclined Displacement 171 cm 3 Bore x Stroke 66 x 50 mm 2 6 x 2 0 in Compression Ratio 5 2 1 Compession Pressure 883 kPa 9 0 kg cm 2 128 psi at 200 r min Starting System Recoil starter Lubrication System Separate lubrication Yamaha Autolube Oil Type or Grade Engine Oil Yamalube 2 cycle oil or Air cooled 2 stroke engine oil Transmission Oil Ya...

Page 77: ... operation Gear Ratio 1st 35 10 3 500 2nd 31 14 2 214 3rd 28 18 1 556 4th 25 21 1 190 5th 23 23 1 000 Chassis Frame Type Semi double cradle Caster Angle 23 30 Trail 76 mm 2 99 in Tire Type Tubeless With tube Size F 22 x 11 8PR Size R 22 x 11 8PR x 2 Tire Pressure Cold tire Reference Tire Pressure F 14 7 kPa 0 15 kg cm2 2 2 psi R 14 7 kPa 0 15 kg cm2 2 2 psi Minimum Tire Pressure F 11 8 kPa 0 12 kg...

Page 78: ...rp Limit 0 Cylinder Bore Size Taper Limit Out of Round Limit Piston Piston Size Measuring Point 2 Piston Clearance Limit Oversize 1st I 2nd 3rd 4th Piston offset YT175J Coil spring oil damper 100 mm 4 0 in C D I Magneto Flywheel magneto Semi sealed beam Bulb type 25W 25Wx 1 5 3Wx 1 3Wx1 YT175J 0 05 mm 0 002 in Lines indicate straightedge measurement 66 mm 2 6 in 0 05 mm 0 002 in 0 01 mm 0 0004 in ...

Page 79: ...acturelQuantity 1 0 Mark Main Jet Main Air Jet Jet Needle clip Position Needle Jet Cutaway Pilot Jet Pilot Outlet Size Air Screw turns out M J M A J J N N J C A P J P O P A S YT175J Keystone B 1 S mm 0 06 in T 2 S mm 0 98 in Plain B 1 S mm 0 06 in T 2 S mm 0 98 in 0 3 O S mm 0 012 0 020 in 0 3 O S mm 0 012 0 020 in 0 04 0 08 mm 0 002 0 003 in 0 04 0 08 mm 0 002 0 003 in 56 8 Bmm 2 2 in 4 0 03 mm 0...

Page 80: ... Sprocket wheel Foot rest Brake pedal Rear bumper B Chassis Model Steering System Steering Bearing Type No Size of Steel Balls Upper Lower 01 0 2 0 01 4 YT175J 25 1 mm 0 9B 0 04 in 1 600 50 r min SUS 0 2 mm 0 008 in 9 mm 0 35 in 0 2 mm 0 008 in Separate lubrication Yamaha autolube pump Green 0 20 0 25 mm 0 008 0 01 in 1 B5 2 05 mm 0 07 O OB in 0 B14 cm 3 0 1Blmp oz 0 03 US oz 3 29 cm3 0 72 Imp oz ...

Page 81: ...ake Pedal Brake Lever Free Play Brake Pedal Position Brake Pedal Free Play 100 mm 4 0 in 341 1 mm 13 43in YT175J Kl 4 9 N mm 0 5 kg mm 28Ib in 0 95mm 0 3 7in K2 9 8 N mm 1 kg mm 56 0 Ib in 95 100 mm 3 7 3 9 in Yes 116cm3 4 08Imp oz 3 92 US oz 245 5 mm 9 67 in From top of inner tube fully compressed without spring Yamaha fork oil 10 15 wt 1 5 mm 0 06 in Disc Wheel Disc Wheel 8 25 x 81 Steel 8 25 x ...

Page 82: ...ut M12 55 5 5 40 Clutch boss M12 38 3 8 27 Drive sprocket M16 55 5 5 40 Change pedal M8 15 1 5 11 Generator Rotor M12 70 7 0 51 Stator M6 13 1 3 10 Engine drain plug M8 20 2 0 14 5 c Electrical Model YT175J Voltage 6V Ignition System Ignition Timing B T D C 20 2 at 2 000 r min 1 86 mm 0 073 in Advancer Type Electrical 30 Cl c E i 020 r c r o co c 10 0 2 4 6 8 10 Engine speed x 103 r min 7 7 ...

Page 83: ... F6T411 MITSUBISHI Minimum Spark Gap 9 mm 0 35 in at 500 r min Primary Winding Resistance 1 0Q 20 at 20 C 68 F Secondary Winding Resistance 5 9KQ 20 at 20 C 68 F Charging System Type Flywheel magneto Lighting Voltage 6V or more at 3 000 r min 8 3Vor less at 8 000 r min 8 v V 6 V Q Ol I 4 Ol c Ol 2 i 0 2 4 6 8 Engine Speed x 10 r min Lighting Coil Resistance Color O 46Q 10 at 20 C 68 F YI R B Oil L...

Page 84: ...l for clean dry threads Components should be at room ternperature DEFINITION OF UNITS Unit Read Definition mm millimeter 10 3 meter em centimeter 10 1meter kg kilogram 103 gram N Newton 1 kg xm sec1 Nm Newton meter NXm m kg Meter kilogram mXkg Pa Pascal N m1 N mm Newton per millimeter N mm L Liter cm 3 Cubic centimeter r min Rotation per minute 7 9 General torque A B specifications Nut Bolt m kg f...

Page 85: ...4 mph mph 1 609 km hr km 0 6214 mi mi 1 609 km m 3 281 ft ft 0 3048 m m 1 094 yd yd 0 9141 m em 0 3937 in in 2 54 em mm 0 03937 in in 25 4 mm ee em3 0 03382 oz USliq oz USliq 29 57 ee em3 ee em3 0 06102 euin eu in 16 387 ee em 3 lit liter 2 1134 pt US liq pt USliq 0 4732 lit liter lit liter 1 057 qt US liq qt US liq 0 9461 lit liter lit liter 0 2642 gal USliq gal USliq 3 785 lit liter kg mm 56 007...

Page 86: ...EXPLODED DIAGRAMS CYLINDER HEAD CYLINDER 20 Nm 2 0 m kg 14 5ft lb 30 Nm 3 0 m kg 22 ft Ib 135Nm 3 5 m kg 25ft lb 1 7 11 ...

Page 87: ...08 PISTON RING END GAP LlMI m 0 020 in TOP 2ND 0 _50__ 6304C3 BEARING B PISTON C mm 0 0016 _ o LEARANCE 0018 in 0040 0 045 62115C41 7 12 BEARING B MHSD25408 o mm 2 0 002 D TrI lHI A 56 0 05 m 0 0012 in CRANK WI iT C 0 03 m RUNOUT LIM 2 0 in ...

Page 88: ...CRANKCASE GASKET 20 Nm 2 0 m kg 14 5 ft Ib 7 13 PANHEAD SCREW Bolt Thread size A M6 B M6 C M6 0 M6 Length 50 mm 2 0 in 60 mm 2 4 in 70 mm 2 8 in 75 mm 3 0 in ...

Page 89: ...TRANSMISSION 1ST WHEEL 5TH WHEEL 3RD WHEEL 4TH WHEEL DOG CLUTCH DRIVE AXLE 6 Nm 0 6 m kg 4 3ft lbl OIL SEAL 55 Nm 5 5 m kg 40 ft Ibl MAIN AXLE 5TH PINION 3RD 4TH PINION 2ND PINION 7 14 ...

Page 90: ...CLUTCH OFF SPRING CHECK L PRESSURE PLATE 3 38 Nm 3 8 m kg 27 ft lb BOSS BALL 8 pes 55 Nm 5 5 m kg 40 ft Ib PRIMARY DRIVEN GEAR 7 15 PRESSURE PLATE 2 THRUST PLATE ...

Page 91: ...SHIFT CAM FORK 14Nm 14 m kg 10f t lb STOPPER LEVER GUIDE BAR 1 SHIFT FORK 1 SHIFT CAM ASSEMBLY SHIFT FORK 2 GUIDE BAR 2 7 16 ...

Page 92: ...SHIFT SHAFT PEDAL SHIFT LEVER SHIFT GUIDE GUIDE O RING SHIFT 10 SHAFT OIL SEAL i Z r BALL JOINT JOINT 7 17 ...

Page 93: ...STEERING ft lbl 50 Nm 15 0m kg 36 34 Nm 13 4 m kg 24 5ft lbl 37Nm 137 m kg 27ft lbl RACE COVER FRONT PANEL 7 18 ...

Page 94: ... f r I I I I I r 1 I I JS I I I I I I I II I I S I d I Ii fifi i 1 O RING I I f 11 I D I I Ii I I I I I I 1 I I I e I I I __ I I I ISNmIO Sm kg L _______ 1 I 4 3ft lbl SNmIO Sm kg I r 4 3ft lbl 1_ I L________ _ __J 23 Nm 12 3 m kg 4 3 ft Ibl 7 19 ...

Page 95: ...FRONT WHEEL AXLE WHEEL COLLOR 2 25 11 8PR TIRE OIL SEAL BEARING IB62031 SPACER I l 1 HUB BEARING B6203 OIL SEAL 7 20 ...

Page 96: ...REAR WHEEL 110 Nm 111 m kg SOft lbl TIRE 12 25 11 8PRI BEARING DRIVEN SPROCKET I39TI 46 Nm 14 6 m kg 33ft lbl 7 21 ...

Page 97: ...ELECTRICAL T OIL WARNING ONCOIL 8Nm O 8m k _ _ 9g 5 8ft lb CHARGE COIL 70Nm 7 0m kg 50 ft Ib 7 22 ...

Page 98: ...nsion pipe Air bleed pipe Over flow pipe Muffler Clamp overflow pipe and air bleed pipe Brake cable foot Pass under seat rail and pass over the muffler Brake cable hand Pass through under seat rail and outside of air cleaner ea e Brake cable hand should pC ss over brake cable foot sE 9 t S T Throttle wire and wire harness Route along left side of main pipe Band Breather pipe Oil pipe Clamp wire ha...

Page 99: ...il pump cable Clamp Ground lead wire Secure together with ignition coil Brake cable On the band side White mark Bring it out of the chain case Oil breather pipe routing diagram Clamp fuel pipe Spring should be positioned in front of white mark Cover with cap Fuel pipe Air bleed pipe Air bleed pipe From crankcase Starter cable Carburetor piping diagram Insert pipes into open I x rn I_end of main pi...

Page 100: ...ENGINE STOP SWITCH OIL WARNIN l CHECKER r YT175J WIRING DIAGRAM Q I __ I AL_____ C D 1 MAGNETO IGNITION COIL OIL LEVEL GAUGE SPARKPLUG L ...

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