Engine Removal

ENGINE REMOVAL

NOTE:
It is not necessary to remove the engine in order to remove the cylinder head, cylinder, or pistons.

A . Preparation for Removal

1 All dirt, mud, dust and foreign material should be thoroughly removed from the exterior of the engine before removal and disassembly. This will help prevent any harmful foreign material from getting into the engine oil.

2. Before the engine removal and disassembly, be sure that you have the proper tools and cleaning equipment so that you can perform a clean and efficient job.

3. During disassembly of the engine, clean and place all of the parts in trays in order of disassembly. This will speed up assembly time and help insure correct reinstall-action of all the engine parts.

4. Place the motorcycle on its center stand. Start the engine and allow it to warm up. Stop the engine and drain the engine and middle gear oil.

5 . Remove the oil filter element from the crankcase.

6. Remove the left and right side covers.

B. Seat and Fuel Tank

1. Turn the fuel petcock to "ON".

2. Remove the seat and the fuel tank holding bolt. Lift the rear end of the duel tank and disconnect the fuel pipes and vacuum pipe from the petcock.

3. Remove the tool tray.

C. Mufflers

1 Remove the rear brake pedal.

2. Remove the exhaust pipe holding nuts from the cylinder head.

3, Loosen the clamp bolts securing the muffler joints.

4. Remove the bolts holding the right and left mufflers to the muffler bracket and remove the left and right mufflers.

D. Battery Case

1. Remove the negative battery cable from the battery terminal then remove the positive battery plate. Remove the battery.

2. Remove the battery case holding bolts and remove the battery case.

E. Air Cleaner Case

1, Remove the ignitor unit mounting board securing screw and disconnect all connectors. Remove the board assembly.

2. Remove the clamps holding the carburetors to the air cleaner case and intake manifolds. Remove the crankcase ventilation hose at the air cleaner case.

3. Remove the bolts holding the air cleaner case to the frame (left and upper)

NOTE
The engine ground wire is secured together with left side holding bolt.

4. Remove the starter (CHOKE) cable from the carburetor.

5. Remove the air cleaner joint rubbers and pull the carburetor assembly to the rear.

6. Disconnect the throttle cable from the carburetor throttle lever and remove the carburetor assembly to the right.

F. Wiring and Cables

1. Disconnect the clutch cable at the crank-case side.

2. Remove the spark plug lead wires and the tachometer cable.

3. Disconnect the electric starter cable at the starter relay switch.

1. Starter relay switch 2. Electric starter cable

4. Disconnect the pick-up coil and ACG lead wire couplers. Position the disconnect lead wires so that they can be safely removed.

CAUTION:
The ACG lead, starter cable, and pickup lead are clamped at the upper cross tube of the frame. Do not forget to remove this clamp before removing the engine.

1. Clamp

5. Remove the horn and flasher relay.

G. Drive Shaft Joint

1 Remove the coil spring holding the rubber boot.

2. Pull the rubber boot from the drive shaft coupling to expose the joint bolts.

3. Remove the joint bolts on the drive

H. Engine Removal

1. Remove the front engine mounting bolts and nuts. Remove the brackets.

1. Front engine mounting bolts 2. Engine stay

NOTE:
It is advisable to hold the engine with a suitable garage jack before removing the engine mounting bolts and nuts.

2. Remove the rear engine mounting bolt and right and left footrests. Remove the brake pedal and right side muffler bracket holding bolt and remove the muffler bracket assembly.

3. Slide the engine forward slightly and remove the engine to the right.

NOTE:
Position a box or other support to the right side of the motorcycle for the assistance when removing the engine.

Cylinder Head Removal

ENGINE OVERHAUL

A. Cylinder Head and Cylinder

1. Remove the cylinder head cover.

2. Remove the left crankcase cover (pickup coil cover).

3. Remove the cam chain tensioner.

4. Use a 19 mm wrench on the timing plate flats to rotate the crankshaft counterclockwise until the engine is at T.D.C.

Caution:
Never use an alien wrench to rotate the crankshaft. Always use the 19 mm flats provided on the timing plate to rotate this engine.

5. Remove the four cam sprocket bolts.

6. Slip each sprocket off its mounting boss on the cam.

CAUTION:
From this point on, do not rotate the cam shaft or valve damage may occur. On this, it is not necessary to break the cam chain. However, it can be broken if so desired. It is easier to disassemble the engine without separating the chain.

7. Remove the cam chain guide.

1, Cam chain guide

8. Remove the cam caps. Note the location of the cam caps. The caps for the intake cam shaft are identified 1-1 through I-3. The exhaust cam caps are identified E-1 through E-3. Directional arrows are cast on each cap and point toward the clutch side.

9. Fasten safety wire to the cam chain to prevent its falling into the crankcase cavity.

Slide the cams and sprockets from under the chain and remove the cams and sprockets.

10. Remove the front cam chain guide.

1. Front cam chain guide

11. Remove the spark plugs.

12. Remove the cylinder head bolts and nuts in the numerical order as shown. Start by loosening each nut 1/2 turn until all of the nuts are loose. Remove the cylinder head.

Piston, Pickup Coil, Shifter, Starter, Generator and Clutch Removal

C. Piston

1. Mark each piston to aid in reassembly.

2. Place a clean towel or rag into the crank-case to keep circlips and material from falling into the engine.

3. Remove piston pin clips, piston pins, and pistons.

D. Pick-up Coil Assembly

1. Remove the alien bolt that holds the timing plate.

2. Remove the pick-up coil securing screws and remove the pick-up coil assembly.

E. Shifter

1. Remove the change pedal.

2. Remove the left crankcase cover.

3. Remove the shift lever assembly and shift shaft assembly.

1. Shift lever assembly 2. Shift shaft assembly

4. Remove the middle gear case oil level maintaining plug.

F. Starter Motor and Generator

1. Remove the starter motor securing bolts and remove the motor assembly.

2. Remove the generator cover and stator coil assembly.

3. Install the rotor holding tool (special tool) on the rotor as shown and remove the rotor holding bolt.

1. Rotor holding tool

4. Invert the holding tool as shown and insert the rotor puller adapter (special tool) into the rotor shaft and screw in the rotor puller (special tool). Remove the rotor.

1. Rotor puller adapter

G. Clutch

1. Remove right crankcase cover.

2. Release the tension evenly on the 6 mm bolts and remove the clutch pressure plate and clutch springs.

3. Remove the friction plates and clutch plates.

4. Straighten the lock washer tab. Use the clutch boss holder (special tool) to hold the clutch boss and remove the lock nut and lock washer.

1. Clutch boss holder

5. Remove the clutch boss and spacer.

6. Screw in a suitable length of 6 mm bolt into the one of the threaded holes on the collar and pull out the collar and needle bearing from the primary driven gear.

1. Collar

7. Remove the primary driven gear assembly and oil pump drive sprocket.

Lower Crankcase Disassembly

L. Lower Crankcase

1. Remove the dowel pin and "O-ring".

2. Remove the shift fork guide bar and shift forks. The shift forks are identified by numbers cast on their sides.

3. Remove the bolt securing the shift cam locating pin and remove the stopper plate and locating pin.

4. Remove the neutral switch.

1. Shift cam locating pin 2. Neutral switch

5. Pull out the shift cam.

6. Remove the driven shaft bearing cover holding screws and remove the bearing cover.

7. Remove the bearing and 5th wheel gear from the driven shaft and pull out the driven shaft assembly.

1. 5th wheel gear

Cylinder Head and Valves -- Inspection & Repair

INSPECTION AND REPAIR

A. Cylinder Head Cover

Place head cover on a surface plate. There should be no warpage. Correct by re-surfacing as follows:

Place #400 or #600 grit wet sandpaper on surface plate and re-surface head cover using a figure-eight sanding pattern. Rotate head cover several times to avoid removing too much material from one side.

B. Cylinder Head

1. Using a rounded scraper, remove carbon deposits from combustion chamber. Take care to avoid damaging spark plug threads and valve seats. Do not use a sharp instrument. Avoid scratching the aluminum.

2. Check the cylinder head warpage with a straight edge as shown.

The warpage should not exceed the specified limit, if necessary resurface. If the warpage exceeds allowable limit, the cylinder head should be replaced with a new one.

Cylinder head warpage: less than 0.05 mm (0.002 in) Allowable limit: 0.25 mm (0.010 in)

C. Valve, Valve Guide, and Valve Seat

1. Check the valve face and the stem end for wear. If the valve face and/or the stem end are pitted or worn, regrind the valve with a valve refacer. Replace the valve if any dimension exceeds the specifications in the illustration.

2. Valve stem wear must be measured and then combined with valve guide measurements to guide clearance. This clearance must be within tolerances. If it exceeds the maximum limit, then replace either or both valve and guide, as necessary.

	Valve Stem Clearance	Maximum
Intake	0.010 — 0.037 mm (0.0004-0.0015 in)	0.10 mm (0.004 in)
Exhaust	0.025-0.052 mm (0.0010-0.0020 in)	0.12 mm (0.005 in)

3. Valve stem end

Inspect the end of the valve stem. If the end appears to be "mushroomed" or has a larger diameter than the rest of the stem, the valve, valve guide, and oil seal should be replaced.

4. Turn valve on "V" blocks and measure the amount of stem runout with a dial gauge. If it exceeds the maximum limit, replace the valve.

Maximum valve stem runout: 0.03 mm (0.0012 in)

5. Valve guide and valve oil seal replacement If oil leaks into the cylinder through a valve due to a worn valve guide, or if a valve is replaced, the valve guide should also be replaced.

NOTE:
The valve oil seal should be replaced whenever a valve is removed or replaced.

a. Measure valve guide inside diameter with a small bore gauge. If it exceeds the limit, replace with an oversize valve guide.

Guide diameter (I.D.):

Limit: 7.10 mm (0.280 in)

b. To ease guide removal and reinstallation, and to maintain the correct interference fit, heat the head to 100°C (212°F). Use an oven to avoid any possibility of head warpage due to uneven heating.

c. Use the appropriate shouldered punch (special tool) to drive the old guide out and drive the new guide in.

NOTE:
When a valve guide is replaced, the O-ring should also be replaced.

1. Valve guide remover

2. Valve guide installer

d. After installing the valve guide, use the 7 mm reamer (special tool) to obtain the proper valve guide to valve stem clearance.

e. After installing the valve guide in the cylinder head, the valve seat must be recut. The valve should be lapped to the new seat.

6. Grinding the Valve Seat

a. The valve seat is subject to severe wear. Whenever the valve is replaced or the valve face is re-surfaced (see caution) the valve seat should be re-surfaced at a 45° angle. If a new valve guide has been installed the valve seat must be recut to guarantee complete sealing between the valve face and seat.

CAUTION:
If the valve seat is obviously pitted or worn, it should be cleaned with a valve seat cutter. Use the 45° cutter, and when twisting the cutter, keep an even downward pressure to prevent chatter marks.

If cutting section "A" of the valve seat, use 30° cutter. If cutting section "B", use the 45° cutter. If cutting section "C" use 60° cutter.

b. Measure valve seat width. Apply mechanic's bluing dye (such as Dykem) to the valve face and valve seat, apply a very small amount of fine grinding compound around the surface of the valve face insert the valve into position, and spin the valve quickly back and forth. Lift the valve, clean off all grinding compound, and check valve seat width. The valve seat and valve face will have removed bluing wherever they contacted each other. Measure the seat width with vernier calipers. It should measure approximately 1.1 mm (0.0433 in). Also, the seat should be uniform in contact area. If valve seat width varies, or if pits still exist, further cutting will be necessary. Remove just enough material to achieve a satisfactory seat.

	Standard Width	Wear Limit
Seat width	1.0 ±0.1 mm (0.0394 ± 0.0039in)	2.0 mm (0.080 in)

a. Seat width

c. If the valve seat is uniform around the perimeter of the valve face, but is too wide or not centered on the valve face, it must be altered. Use either the 30°, 45° or 60° cutters to correct the improper seat location in the manner described below:

1) If the valve face shows that the valve seat is centered on the valve face, but too wide, then lightly use both the 30° and the 60° cutters to reduce the seat width to 1.1 mm (0.0433 in).

1. Valve seat cutter

2) If the seat shows to be in the middle of the valve face, but too narrow, use the 45°cutter until the width equals 1.1 mm (0.0433 in).

3) If the seat is too narrow and right up near the valve margin, then first use the 30° cutter and then the 45° cutter to get the correct seat width.

4) If the seat is too narrow and down near the bottom edge of the valve face, then first use the 60° cutter and then the 45° cutter.

7. Lapping the valve/valve seat assembly a. The valve/valve seat assembly should be lapped if neither the seat nor the valve face are severely worn.

b. Apply a small amount of coarse lapping compound to valve face. Insert the valve into the head. Rotate the valve until the valve and valve seat are evenly polished. Clean off the coarse compound, then follow the same procedure with fine compound.

Continue lapping until the valve face shows a complete and smooth surface all the way around. Clean off the compound material. Apply bluing dye to the valve face and seat and rotate the valve face for full seat contact which is indicated by a grey surface all around the valve face where the bluing has been rubbed away.

c. Valve leakage check

After all work has been performed on the valve and valve seat, and all head parts have been assembled, check for proper valve/valve seat sealing by pouring solvent into each of the intake ports, then the exhaust ports. There should be no leakage past the seat. If fluid leaks, disassemble and continue to lap with fine lapping compound. Clean all parts thoroughly, reassemble and check again with solvent. Repeat this procedure as often as necessary to obtain a satisfactory seal.

Valve Springs and Lifters, Camshafts, Chain and Guides -- Inspection and Repair

D. Valve Spring and Lifters

1. Checking the valve springs

a. This engine uses two springs of different sizes to prevent valve float or surging. The valve spring specifications show the basic value characteristics.

b. Even though the spring is constructed of durable spring steel, it gradually loses some of it's tension. This is evidenced by a gradual shortening of free length. Use a vernier caliper to measure spring free length. If the free length of any spring has decreased more than 2 mm (0.080 in) from its specification replace it.

c. Another symptom of a fatigued spring is insufficient spring pressure when compressed. This can be checked using a valve spring compression rate gauge. Test each spring individually. Place it in the gauge and compress the spring first to the specified compressed length with the valve closed (all spring specifications can be found in the previous section, Valve Spring), then to the length with the valve open. Note the poundage indicated on the scale at each setting. Use this procedure with the outer springs, then the inner springs.

NOTE:
All valve springs must be installed with larger pitch upward as shown.

Valve Spring Specifications
	OUTER	INNER
Free length	39.5 mm (1.55 in)	35.9 mm (1.413 in)
Installed length (valve closed)	34.0 mm (1.339 in)	31.0 mm (1.220 in)
Installed pressure	19.1 kg (42.1 lb)	9.0 kg (19.8 1b)
Allowable tilt from vertical	1.6°

2. Valve lifter

a. Check each valve lifter for scratches or other damage. If the lifter is damaged in any way, the cylinder head surface in which it rides is probably also damaged. If the damage is severe, it may be necessary to replace both the lifter and the cylinder head.

NOTE:
For proper valve lifter-to-head clearance, always install lifters on their original valves.

E. Camshafts, Cam chain and Cam Sprockets

1. Camshaft

a. The cam lobe metal surface may have a blue discoloration due to excessive friction. The metal surface could also start to flake off or become pitted.

b. If any of the above wear conditions are readily visible, the camshaft should be replaced.

c. Even though the cam lobe surface appears to be in satisfactory condition, the lobes should be measured with a micrometer. Cam lobe wear can occur without scarring the surface. If this wear exceeds a pre-determined amount, valve timing and lift are affected. Replace the camshaft if wear exceeds the limits.

d. Install the camshaft on the cylinder head. Place a strip of Plastigage between camshaft and camshaft cap as illustrated (lengthwise along camshaft). Tighten the nuts with specified torque. Remove the camshaft cap and determine the clearance by measuring the width of the flattened Plastigage.

Cap nut tightening torque: 1.0m-kg (7.2ft-lb)

1. Plastigage

NOTE:
Do not turn camshaft when measuring clearance with Plastigage.

Camshaft-to-cap clearance:

Standard:	0.020-0.054 mm
	(0.0008- 0.0021 in)
Maximum:	0.160 mm (0.006 in)

If the camshaft-to-cap clearance exceeds specification, measure camshaft bearing surface diameter.

Bearing surface diameter:

Standard:	24.967-24.980 mm
	(0.9830-0.9835 in)

1) If camshaft diameter is less than specification, causing excessive clearance, replace camshaft.

2) If camshaft is within specification and camshaft-to-cap clearance is excessive, replace cylinder head.

2. Cam chain

Except in cases of oil starvation, the cam chain wears very little. If the cam chain has stretched excessively and it is difficult to keep the proper cam chain tension, the chain should be replaced.

3. Cam sprockets

Check cam sprockets for obvious wear.

4, Cam chain dampers and tensioner