Valve Tappets And Guides

GENERAL

Tappets and tappetguides seldom require replacement. Primarily, they are only removed for the purpose of checking end play of the cam gears, when reassembling an engine.

DISASSEMBLING (Figure 3-30)

Clean all dirt from around crankcase and blow loose particles from the area with compressed air. Remove push rods. This procedure is covered under "REMOVING AND INSTALLING PUSH RODS," this section.

For 1976 and earlier models guides are press fit into crankcase (see "SPECIFICATIONS," this section). Remove tappet guide screw (1) and tappet adjusting screw (2) and slide

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Figure 3-29. Gerotor Wear Limits

Figure 3-29. Gerotor Wear Limits

Tappet Guide Puller, Part No. 95724-57, in mating grooves of tappet guide (3). Before turning tappet guide (3) from crankcase, be sure cam gear is installed in case for tappet to butt against when using puller (see Figure 3-31). For 1977 and later models, remove tappet guide screw (1) and remove tappet guide (3). It may be necessary to remove cylinders to remove front and rear intake tappet guides. Mark valve tappets in some manner to identify them as to location.

It is good practice to reassemble valve tappets and valve tappet guides in the same place from which they were removed. This will ensure an even wear pattern between tappet, guide and cam surface.

CLEANING AND INSPECTING (Figure 3-30)

Clean all parts thoroughly in cleaning solvent and blow dry with compressed air. Inspect valve tappets for excessive clearance in guides. Valve tappets should be loose in tappet guides. Excessive tappet-guide clearance is serviced by fitting new tappet, and/or new guide. It is recommended practice to replace complete tappet when only the roller is excessively loose or badly worn; however, it is possible to replace tappet roller kit (6) individual parts. If this is done, roller must turn freely on needle bearings and have side-play after new roller pin is securely riveted to tappet. See "SPECIFICATIONS."

If end of valve tappet adjusting screw is damaged, worn egg shaped or pitted from action of push rod, it should be replaced to ensure accurato tappet-valve stem adjustment.

Discard O-ring (5, Figure 3-30) and replace with a new one.

ASSEMBLING (Figure 3-30)

Assembly is essentially the reverse order of disassembly. Apply a light coat of oil to the tappet and in particular, the tappet roller assembly and O-ring. If tappet is not located correctly in guide, tappet roller will be crosswise to guide and cam, and serious damage may result when installed in crankcase.

1.

Tappet guide screw

15.

Gearcase cover gasket

2.

Tappet screw with nut

16.

Flywheel shaft pinion gear

3.

Tappet guide

17.

Oil pump drive gear

4.

Tappet and roller

18.

Cam gear needle

5.

Tappet guide O-ring

roller bearing (4)

6.

Tappet roller kit

19.

Rear exhaust cam gear

7.

Rear cylinder exhaust cam gear

shaft bushing

25. Oil separator bushing

8.

Rear cylinder intake cam gear

20.

Cam gear and timer shaft

26. Crankcase oil strainer,

9.

Front cylinder intake cam gear

bushing

retaining pin and gasket

10.

Front cylinder exhaust cam gear

21.

Pinion gear shaft bushing

(1976 and earlier)

11.

Cam gear plate (2)

22.

Front intake cam gear

27. Gearcase cover bushing

12.

Cam shaft washer - .005, .007 in.

shaft bushing

pin (7)

13.

Idler gear

23.

Front exhaust cam gear

28. Idler gear shaft

14.

Idler gear shaft fiber

shaft bushing

29. Lockwasher (1977 and later)

washer (1975 & earlier)

24.

Idler gear shaft bushing (2)

30. Nut (1977 and later)

Figure 3-30. Gearcase and Tappet - Exploded View

3-29

Pull tappet out to limit of travel and hold in place with a clip or other means to prevent tappet from dropping into crank-case when installing the assembly.

Insert new O-ring (5) on guide (3). Assemble adjusting screw and nut (2) in tappet (4) and then insert tappet into guide (3). Align screw holes in tappet guide with screw holes in crankcase and install assembly using a piece of tubing or a block of soft wood. Tappet guides are a soft malleable cast iron, therefore, be extremely careful nottodam-age the guide during installation. With screw (1) in place, recheck free movement of tappet in guide.

Figure 3-31. Removing Tappet Guide (1976 and Earlier)

GEARCASE COVER AND CAM GEARS

DISASSEMBLING (Figure 3-32 and Figure 3-33)

Thoroughly clean area around gearcase cover and tappets. Blow all loose dirt from crankcase with compressed air. Loosen exhaust pipe port clamps (1) and muffler clamps and lower exhaust pipe free of gearcase cover. Remove footrest (2), gear shift foot lever (3), 1974 and earlier, and breather pipe (4). For models 1975 and later, remove footrest (2), along with rear brake foot lever (3A), and breather pipe (4). On 1970 models remove circuit breaker (5).

Remove push rods (7) as described in "REMOVING AND INSTALLING PUSH RODS."

On 1971 models, remove two circuit breaker cover screws, cover and gasket. Remove circuit breaker cam assembly bolt, two circuit breaker hold down screws, lockwashers and washers or retainer and circuit breaker advance assembly. See "CIRCUIT BREAKER" Section 5.

Place a pan under gearcase to collect oil when cover is removed. Remove gearcase cover screws (8) and generator mounting screws (9). Free cover from crankcase. Cover is located on dowel pins which fit rather snugly. The cover must be worked off these pins carefully to avoid damage to joint faces. Do not pry off with screwdriver inserted between joint faces. Use a hammer and a block of wood, and

1. Exhaust pipe port clamp (2)

2. Footrest

3. Gear shift foot lever

4. Breather pipe

5. Circuit breaker

6. Gearcase cover

8. Gearcase cover screw (11)

9. Clutch cable

Figure 3-32. Removing Gearcase Cover (1970)

tap lightly at the end where the cover projects beyond the gearcase. Note that oil tank vent hose is clamped to gear-case cover fitting and must be disconnected before cover can be completely removed from motorcycle.

Remove valve tappets and valve tappet guides only to establish correct cam gear end play. See "VALVE TAPPETS AND VALVE TAPPET GUIDES." On 1970 models, pull clutch cable (9) forward (as positioned on motorcycle), at the same time press cable inward and down to free from gear-case cover.

Refer to Figure 3-30 and proceed as follows. Remove cam gears (7, 8, 9 and 10) and cam gear plates (11). (Cam gears are numbered on cam lobe from one to four, from the rear exhaust valve cam forward.) When cam gears are removed, note whether or not cam gears have thin steel spacing washers (12) on either end of cam gear shafts. If any of the cam gears mentioned have spacing washers, be sure the same ones are used on each shaft when reassembling if the same cam gears and case cover are used again.

3-30

3-30

1. Exhaust pipe port clamp (2)

2. Footrest

3. Gear shift foot lever (1974 & earlier) 3A. Rear brake foot lever (1975 & later)

4. Breather pipe (1976 & earlier)

5. Circuit breaker

6. Gearcase cover

8. Gearcase cover screw (11)

9. Generator mounting screws (3)

Figure 3-33. Removing Gearcase Cover (1971 and Later)

rree idler gear (13) with fiber washer (14) by lifting generator up and away from crankcase. Discard gasket (15). On 1976 and earlier models pinion gear (16) is a press fit on pinion shaft splines, remove with Pinion Gear Puller, Part No. 96830-51. On 1977 and later models, pinion gear is a slip fit. Remove nut (30) and lockwasher (29) and remove pinion gear from pinion shaft. Oil pump drive gear (spiral gear) (17) is located on splined shaft behind pinion gear. Remove spiral gear which is a slip fit on splines.

CLEANING AND INSPECTING (Figure 3-30)

With cleaning solvent thoroughly scrub the gearcase cover and gears to remove any oil and carbon deposits. Blow out all gearcase cover oil passages and bushings with compressed air. Clean old gasket sealer from joint faces with cleaning solvent. Carefully examine timing gears for excessive wear by inserting gears in case cover. Check for looseness in bushings and for amount of lash between gears. If teeth are pitted, scored, cracked, chipped or if faces of teeth are worn, replace gears. Check the gear shafts for damage and pitted surfaces. Measure shafts and bushings with appropriate instruments to determine extent of wear. If any cams are found with rough or pitted surfaces, replace gear. The idler gear shaft (28) is a press fit in the gear and can be replaced, providing the gear is in good condition.

On 1976 and earlier models, check pinion gear (16) for press fit on pinion shaft. The slightest lash will usually re sult in noisy operation, often mistaKeniy attrmutea to tne other timing gears.

Check cam gear needle roller bearings (18) and idler gear bushings (24) in right crankcase side and cam gear shaft and pinion gear shaft bushings (19,20,21,22,23 and 24) in gearcase cover for extent of wear. These bushings normally do not require replacement until an engine has run up extremely high mileage.

See "SPECIFICATIONS," for clearance of cam gear shafts in cover bushings, pinion gear shaft in cover bushing and cam gear shafts in crankcase needle roller bearings.

When bushings are worn to the extent of increasing clearance to .001 in. or more over specified limits, they should be replaced, as the cam gears are likely to become very noisy with excessive clearance in the bushings. Examine the face of each bronze bushing flange for wear. If bushing flanges are badly worn replace bushings.

Examine cam gear plates (11) for excessive wear or damage. Replace, if necessary.

Oil separator bushing (25) should have 1/16 in. ┬▒ 1 /64 in. running clearance with generator oil slinger. If clearance is too great, insert a thin washer between face of gear and oil slinger washer.

On 1976 and earlier models, inspect the crankcase oil strainer (26) to make sure it is not plugged with any foreign material.

REPLACING BEARINGS

The four cam gear needle roller bearings in the crankcase are a press fit and can be removed and installed without disassembling crankcase by using Tool, Part No. 95760-69 as shown in Figure 3-39. Use Tool, Part No. 97273-60, for installing cam gear needle roller bearings, always press on printed side of bearings, being extremely careful not to tip or misalign bearing in the case during the installing operation.

If inspection warrants replacement of either the cam gear or pinion gear bronze bushings in the gearcase cover, it first is necessary to separate the right and left crankcase sides and remove the flywheel assembly. See "CRANKCASE."

To remove the six blind bushings from the gearcase cover and one blind bushing (idler gear) from the crankcase, use Puller, Part No. 95760-69 as shown in Figure 3-34.

Before pressing in new bushings, note location of original dowel pin holes for reference when drilling new holes. When drilling new holes, be sure to locate holes 1 /8 in. or more from original dowel pin holes.

Use a smooth surfaced disc or plate slightly larger than flange when pressing bushing into position. Be sure bushing flanges are seated tight against gearcase cover and/or crankcase idler gear bushing.

After new bushings have been pressed in, they must be dowel pinned with cover bushing pins to prevent them from turning. Drill a hole with a number 31 drill, 9/32 in. deep, through bushing flange and into aluminum so when dowel pin is driven in and bottomed, its end will be slightly below face of bushing flange. Peen bushing around dowel pin hole to prevent pin from coming out.

Figure 3-35. Installing Tool for Line-Reaming Rear Intake Cam Gear Shaft Cover Bushing

After all bronze bushings have been pressed in and dowel pinned, all but the idler gear bushings must be line-reamed.

Parts order bushings are furnished nearly to size so there is little stock to be removed when reaming bushing. When removing reamer, keep turning it to the right as it is being pulled out.

To ream idler gear bushings, use special Reamer, Part No. 94806-57. Carefully align and turn reamer into bushing until it bottoms.

To line-ream the 1 -1 /8 in. dia. rear intake camshaft bushing in the gearcase cover, insert special Reamer, Part No. 94803-37 or use late style Reamer, Part No. 94803-67 and insert through crankcase needle roller bearing. Reamer will be a close fit in needle roller bearing, providing alignment for reaming the gearcase cover bushing.

See Figure 3-35. Install gearcase cover, at same time starting cover bushing reamer in cover bushing. Turn reamer into crankcase and gearcase cover bushings until it bottoms in gearcase cover.

To line-ream the front exhaust, front intake and rear exhaust cam gear shaft bushings in the gearcase cover, assemble the cover to crankcase side. With cover bushing reamer removed, insert special Reamer, Part No. 94803-37 or use a standard 11/16 dia. hand reamer through needle roller bearing, into cover bushing andturn until it bottoms in case cover.

To line-ream the pinion gear shaft bushing, install gear-case cover. Insert steel pilot bushing into crankcase bearing race to guide reamer. Insert special Reamer, Part No. 94812-37A, through pilot bushing into pinion gear shaft bushing, and turn reamer until it bottoms in gearcase cover. Remove gearcase cover.

Figure 3-35. Installing Tool for Line-Reaming Rear Intake Cam Gear Shaft Cover Bushing

ASSEMBLING

1. Check end play of cam gears described below under "DETERMINING CORRECT CAM GEAR END PLAY."

2. For 1976 and earlier, retime the breather valve according to the instructionsunder "TIMING BREATHER VALVE."

3. Install the cam gears and assemble the gearcase cover in place. See "INSTALLING CAM GEARS AND GEARCASE COVER."

4. Install valve tappets and valve tappet guides (if they have been removed). See 'VALVE TAPPETS AND VALVE TAPPET GUIDES."

5. Reassemble circuit breaker. See "CIRCUIT BREAKER," Section 5.

6. Install push rods and adjust tappets as described in "CYLINDER HEAD," and "REMOVING AND INSTALLING PUSH RODS," and "ADJUSTING TAPPETS."

7. Refer to Figure 3-32. Assemble breather pipe (4), gear shift foot lever (3). footrest (2), exhaust pipe port clamps (1) and muffler clamps.

DETERMINING CORRECT CAM GEAR END PUVY (Figure 3-30)

Before final reassembly of the cam gears, correct cam gear end play must be established. Temporarily position the two cam gear plates (11), less shims, in the gearcase compartment. Position against crankcase with beveled side of holes for cam shaft facing outward toward cams. Install cam gears. Assemble the case cover with a new dry gasket and securely tighten screws to 8-10 ft-lbs torque (less genera- | tor bolts).

1. Flywheel timing mark

2. Oil pump drive gear (spiral gear)

3. Pinion gear

4. Timing hole in breather sleeve gear

Figure 3-37. Installing Pinion Gear (1976 and Earlier)

Turn the engine over until the number one cam gear loDe is facing up as viewed through the tappet guide hole in the crankcase. Using a long shank screwdriver, pry the cam gear towards the case cover. With a feeler gauge, measure the clearance (end play) between the cam shaft shoulder Nnd the gear plate. Repeat this operation for remainder of jam gears.

If end play exceeds the maximum specification, add necessary number of .005 to .007 in. thickness steel shims (12) to obtain recommended running clearance. If more than 1 shim is required, equally divide shims on both ends of shaft. After adding shims, turn engine over to be sure cam gears turn freely.

TIMING BREATHER VALVE (1976 AND EARLIER) (Figure 3-36)

1. Flywheel timing mark

2. Oil pump drive gear (spiral gear)

3. Pinion gear

4. Timing hole in breather sleeve gear snouia race outwara against pinion gear wnen assemDiea to shaft.

NOTE

Once breather valve is correctly timed, position of flywheel timing mark and breather valve timing mark, registered in slot of breather sleeve gear, can be disregarded when installing timing gears.

INSTALLING PINION GEAR (Figure 3-37)

On 1976 and earlier models, assemble spiral gear against shoulder on pinion shaft engaging breather sleeve gear tooth which will register timing hole in breather sleeve (4) in center of slot in breather bushing as shown. Install pinion gear using Gear Puller and Installer Tool as shown in Figure 3-37.

Figure 3-37. Installing Pinion Gear (1976 and Earlier)

Figure 3-36. Timing Crankcase Breather (1976 and Earlier)

The breather must be retimed if disengaged from mating oil pump drive gear (spiral gear) on pinion shaft. To check breather timing proceed as follows:

Flywheel timing mark (1) should be exactly in center of timing inspection hole in left side of crankcase.

-Oil pump drive gear (spiral gear) (2) is located on splined laft behind pinion gear (3). Spiral gear is a slip fit on ┬┐lines. A mark is cut on one side of spiral gear, which

Turn screw (1 ) on end of pinion shaft and tighten securely. Position gear locating collar (2) and body (3) on screw (1 ). Turn tool body to press gear into position until locating collar firmly contacts joint face of crankcase. This positions pinion gear outer face exactly 5/16 in. from gearcase joint face, the running position for the gear when case cover is in place.

On 1977 and later models, install pinion gear on shaft with timing marks aligned. Install lockwasher (29, Figure 3-30) and nut (30, Figure 3-30) and tighten to 50 ft-lbs torque.

INSTALLING CAM GEARS AND GEARCASE COVER (Figure 3-38)

Install plates (11, Figure 3-30) in case recess with beveled side of holes for cam shaft facing outward toward cam.

Lubricate cam gear shafts and position in crankcase with marks on gears 1,2,3,4 and 5 in alignment as shown under Figure 3-38. Install idler gear (7) in crankcase with fiber washer (8| toward the cover side.

Position gearcase cover gasket on crankcase. Be sure to install a new factory-made gasket. Never use a homemade gasket as cover gasket has holes especially located for oil passages and if a hole is left out or put in wrong place, oiling system will not function normally.

Lubricate the cam gears with a liberal coating of engine oil. Carefully align cover and tap into position. Cover should slip into place easily and should never be forced or driven into place. Tighten all screws evenly to 8- 10ft-lbs torque, working opposite from one another. Install generator and gasket. Tilt generator back end down as it is inserted in gear-case opening to lift oil slinger over idler gear, and then up to mesh generator and idler gears. Turn engine over to make sure gears turn freely. Figure 3-38. Timing Gears

1. Rear exhaust cam gear

2. Rear intake cam gear

3. Front intake cam gear

4. Front exhaust cam gear

5. Pinion gear

6. Crankcase breather sleeve gear

7. Intermediate gear (has no timing mark)

8. Intermediate gear fiber washer (1976 & earlier)

9. Generator drive gear

Figure 3-39 Removing and Installing Cam Gear Needle Bearings in Crankcase
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