Cylinder Head

REMOVING (Figure 3-3)

Before removing cylinder head assembly, strip motorcycle as described in "Stripping Motorcycle For Engine Repair."

Disconnect overhead oil feed line (1) and cylinder interconnecting oil line (4) at fittings.

Remove spring cap retainers (8) on push rod covers by prying down and out on cover spring cap with screwdriver. Crank engine until valves are closed.

Remove five head bolts (5) from each head. Lift cylinder head enough to slip out push rods (6) and push rod covers (7). Mark push rods so that they will be reassembled in same location. Remove cylinder head (9). Remove cylinder head gasket (10).

DISASSEMBLING (Figure 3-3)

Free the rocker arm cover (13) and gasket (14) from cylinder head by removing stud nuts (11). Before further disassembly, carefully check the rocker arm pads and ball sockets for pitting and excessive wear. Also, check the rocker arm shaft (17) for proper end play.

Remove rocker arm shaft screw and "O" ring (18), acorn nut and washer (15). Discard shaft screw "0" ring. Tap rocker arm shaft (17) from cover and remove rocker arm (20) and spacer (16). Mark rocker arm shaft and arm in some manner so all parts may be returned to respective locations during assembly.

Compress valve springs using Valve Spring Compressor, Part No. 96600-36, and remove valve keys (23) from ends of valve stems as shown in Figure 3-4. Mark keys to identify them with their respective valves. Remove valve spring collars (24 and 27), springs (25 and 26) and valves (28). Reassemble valves in same cylinder head from which they were removed. Before removing, mark valves in some manner to identify them with front and rear cylinder head.

CLEANING AND INSPECTION

Clean outside of cylinder head with a wire brush. Bead blast or scrape carbon from head, top of cylinder, top of bore above ring path, and inlet and exhaust valve ports. When scraping carbon, be careful to avoid scratching or nicking cylinder head and cylinder joint faces or bore. Blow off loosened carbon or dirt with compressed air.

Wash all parts in solvent. Blow out oil passages in head. Be sure they are free of sludge and carbon particles. Remove loosened carbon from valve head and stem with a wire wheel. Never use a file or other hardened tool that will scratch or nick valve. Polish valve stem with very fine emery cloth or steel wool. Check valve stem for excessive wear.

Valve head should have a seating surface about 1/16 in. wide and should be free of pit marks and burn spots. Exhaust valves should contain carbon that is black or dark brown. White or light buff carbon indicates excessive heal and burning.

Valve seats are also subject to wear, pitting and burning. They should be resurfaced whenever valves are refinished. Clean valve guides with an appropriate expansion reamer. Check for valve wear and valve stem clearance.

Inspect spark plug port threads for damage. If threads in head are damaged, a special plug insert can be installed using a standard spark plug port repair kit.

Inspect valve springs for broken or discolored coils. Check free length or check tension of each spring. If a spring is more than 1/8 in. shorter than a new spring, or tension shows spring to be below low limit tension of new spring, replace it with a new spring. Check valve spring compression with valve spring tester against tolerances shown in "Engine Specifications."

Examine push rods, particularly the ball ends. Replace any rods that are bent, worn, discolored or broken. Check cup at end of rocker arm to make certain there are no chips broken out.

Blow out oil passages in rocker arms, rocker arm bushings and rocker arm covers.

If the rocker arm pads show uneven wear or pitting, dress on a grinder, maintaining original curve. If possible, compare with a new unit during this operation to insure a correctly contoured surface.

Carefully check the rocker arm and shaft for wear. Replace rocker arm bushings if shaft is over .002 in. loose in bushings, as described in "Repairing Rocker Arms and Bushings."

REPAIRING ROCKER ARMS AND BUSHINGS (Figure 3-3)

To replace worn bushings (19), press or drive them from the rocker arm. If bushing is difficult to remove, insert a 9/16-18 tap into bushing. From opposite side of rocker arm, drive out bushing and tap. Press replacement bushing into rocker arm, flush with arm end, oil hole correctly aligned and split portion of bushing towards top of arm. Using remaining old bushing as a pilot, ream new bushing with Harley-Davidson Reamer Tool, Part No. 94804-57. Repeat for other end of rocker arm. When reassembling rocker arm housing, install new O-rings (18).

1. Overhead oil feed line

3. Feed line rubber sleeve (3)

4. Cylinder interconnecting oil line

5. Head bolt and washer (5)

8. Spring cap retainer (2)

9. Cylinder head

10. Cylinder head gasket

11. Rocker housing nut and washer (5)

12. Oil feed line nipple

13. Rocker arm housing

14. Rocker housing gasket

15. Rocker arm shaft acorn nut and washer

16. Rocker arm spacer (2)

17. Rocker arm shaft (2)

18. Rocker arm shaft screw and O-ring (2 each)

19. Rocker arm bushing (4)

21. Valve seat insert (one exhaust, one intake)

22. Rocker housing stud (8)

24. Upper valve spring collar (2)

25. Outer valve spring (2)

26. Inner valve spring (2)

27. Lower spring collar (2)

28. Valve (one exhaust, one intake)

29. Valve guide, shouldered (2) (1978-1979) 29A. Valve guide and snap ring (2) (1980)

30. Nut

31. Washer

32. Upper engine mount bracket

Figure 3-3. Cylinder Head — Exploded View

REPLACING VALVE GUIDES

RECONDITIONING OR REPLACING VALVE SEATS

Replacing valve guides if necessary, must be done before valve seat and face are ground since the valve stem hole in valve guide is the basis from which all face and seat grinding is done. Valve stem-valve guide clearances are listed on page 3-1. If valve stems and/or guides are worn to exceed the maximum tolerance by more than .002 in., new parts must be installed.

Tap out valve guides with shouldered drift pin (from chamber side) and insert replacement guide on arbor press. Be particularly careful to press replacement guide squarely into hole.

NOTE: On cast iron guides, install a new snap ring on guide before pressing in.

New valve guides are reamed to correct size. However, when guides are pressed into cylinder heads they may close up slightly; also the ends may be burred. Therefore, after new guides are In place, they should be sized and cleaned with an expansion reamer.

It is of prime importance that valve guides fit tightly in cylinder heads, or valves may not seat properly. If original guide or new standard guide is not a tight press fit, an oversize guide must be installed. Steel guides are available in the following oversizes: intake - .001, .002, .003, .004, .008; exhaust - .001, .003, .004, .006, .008

Cast iron guides are available in the following over-sizes: intake and exhaust - .001, .002, .003, .004, .006, .008 and .025

The number of grooves on O.D. indicates number of thousandths of an inch press diameter is oversize.

After installing valve guides, valve seats must be re-faced to true them with guides.

If valves have been reseated several times, valve seats may have become too wide and/or valve may be seating itself too deeply in head. When valve seat becomes wider than 1/16 in. (see Figures 3-5, 3-5B) valve seat relief must be counterbored or ground to reduce seat to 1/16 in. Counterbore dimensions are shown. Tools for this purpose are available commercially. To determine if valve is seating itself too deeply in head, measure distance from shoulder of valve guide to end of valve stem. See dimensions in Figure 3-5 and 3-5A. When valve stem extends through guide in excess of maximum shown, valve seat inserts must be replaced.

For 1979 and earlier models, a special gage is available under Part No. 96490-59A, which is used to measure this dimension. The tool consists of gage valves and gage which is placed over the valve stem as shown. If top end of gage valve stem is between steps on gage, the valve seat location is satisfactory.

Replacement inserts are available from the factory. Installation requires accurate boring equipment to machine correct counterbore in head for installation with .004 to .006 in. interference fit.

GRINDING VALVE FACES AND SEATS

Valve seat tools and fixtures are available commercially. Seat each valve in same port from which it was disassembled. Correct valve seat angles are shown in Figures 3-5 and 3-5B.

Figure 3-4. Compressing Valve Spring Figure 3-5. Valve Seat — Early 1980 and Earlier

1.645

1.600

Intake valves are marked "IN" on head; exhaust valves are marked "EX."

Figure 3-6. Lapping Valves

1.645

Figure 3-5B. Valve Seat Angles — Late 1980 and Later

LAPPING VALVE FACES AND SEATS

Figure 3-6. Lapping Valves

ASSEMBLING CYLINDER HEAD (Figure 3-3)

Replace valve and valve spring assemblies using Valve Spring Compressor, Part No. 96600-36. Position valve keys so spaces between key halves are equal.

Replace rocker arm assemblies. Rocker arms must be free or hydraulic lifters will not fill with oil. Replace rocker arm cover. New cover gaskets (14) should be used and cover nuts must be tightened evenly to 15 ft-lbs.

CAUTION

Be sure to see that rocker arm ends do not jam against valve stems as rocker box is installed on head studs. Use a screwdriver to raise valve end of arm when cover assembly is Installed.

Install each cylinder head with a new cylinder gasket and position rear head. Start cylinder head bolts. First turn bolts snug, then using a torque wrench tighten each 1/4 turn at a time until all are drawn to 55-60 ft-lbs.

1.600

ateiy reiaceu, very nine lapping win ue requirea to com plete operation. Apply a light coat of fine lapping compound to valve face, insert valve in guide and give it a few turns with Valve Lapping Tool, Part No. 96550-36. Lift valve *nd rotate it about 1/3 of a turn. Repeat lapping procidure as shown in Figure 3-6. After full turn, remove valve, wash valve face and seat, and dry with cloth that is immediately discarded so grinding compound cannot be transferred to engine parts. If inspection shows an unbroken lapped finish of uniform width around both valve and seat, valve is well seated. H lapped finish is not complete, further lapping or grinding and lapping is necessary.

Valve face angle is 45° for both intake and exhaust valves, and if a valve refacing grinder is used, it must be adjusted exactly to this angle. It is important to not remove any more metal than is necessary to clean up and true valve face. If grinding leaves the edge of valve very thin or sharp, install a new valve. A valve in this condition does not seat normally, will burn easily and may cause pre-ignition. There is also danger of cracking. Valves that do not clean up quickly are probably warped or too deeply pitted to be used. If end of valve stem shown uneven wear, true end of stem on a valve refacing grinder equipped with suitable attachment.

Intake valves are marked "IN" on head; exhaust valves are marked "EX."

Figure 3-5A. Measuring Valve Depth — Late 1980 and Later

Head

Figure 3-5B. Valve Seat Angles — Late 1980 and Later

Valve

Head

Valve

If valve faces and seats have been smoothly and accur-3-10

Install push rods as described in the next procedure.

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