Harley Davidson DUO-GLIDE 74 OHV. Service manual (1959) — page 4

CYLINDER HEAD

REMOVING CYLINDER HEAD ASSEMBLY (Fig. 3B-1)

Remove spring cap retainers (1) on push rod covers by prying down on cover spring cap with screwdriver wedged between cylinder cooling fins and pulling spring cap retainers out.

Remove five head bolts and washers (2) from each head. Lift cylinder head enough to slip out push rods (3) and push rod covers (4). Remove cylinder head (5). Remove cylinder head gasket (6). Mark push rods so that they will be reassembled in same position.

DISASSEMBLING CYLINDER HEAD

Remove the 12 cover reinforcing screws (7) and lift off reinforcing ring (8), rocker arm cover (9) and cover gasket (11). Cover pad (10) is cemented inside cover and needs no attention if in serviceable condition.

Turn off the eight rocker arm bearing stud nuts (12), and lift intake valve oiler (13) off studs. Remove rocker arm bearing halves (14 and 16) with rocker arms (15).

Remove exhaust valve stem pads (17). Compress valve springs with Valve Spring Compressor, Part No. 96600-36, as shown in Fig. 3B-2. Remove valve key halves (18).

NOTE

On FLH engines, valve stem pads are not used and valve key is split wedge type.

Remove upper valve spring collar (19), outer valve spring (20) and inner valve spring (21) and lower spring collar (22). Slip valves (23) out of valve guides in head.

Do not interchange valves, rocker arms or rocker arm bearing halves. Either process parts separately or mark them in some manner so they may be returned to their respective positions.

CLEANING AND INSPECTION

Clean outside of cylinder head with a wire brush. 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 Harley-Davidson "Gunk Hydro-Seal". 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 hard-ened 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, it 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 heat and burning.

Valve seats are also subject to wear, pitting and burning. They should be resurfaced whenever valves are refinished. Clean valve guides with the Harley-Davidson Valve Guide Reamer, Part No. 94830-47, and check for wear and valve stem clearance.

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,” Section ЗА.

Examine push rods. Replace any rods that are bent, 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 bearings and replace intake valve oilers. When used valve oilers are cleaned and reinstalled, they invariably allow over-oiling. Assemble units on head (dry) and check rocker arm clearance in bearing. If rocker arm fit in bearing is greater than .002 in., repair bearings that are otherwise serviceable as follows: Remove locating dowel pins from bearing covers and sand matching faces of top and bottom rocker arm bearing halves on a sheet of emery cloth laid on a fairly true firm surface. Sand both halves an equal amount. Wash parts and assemble (with dowel pins) to cylinder head, but omit rocker arm. Line ream hole in bearing with a standard 7/8 in. reamer. Disassemble, wash parts and reassemble, including rocker arm. Check fit and repeat sanding and reaming procedure until desired tolerance fitting is reached. Rocker arms must be free in bearings or hydraulic lifters will not fill with oil. Always strike sides of rocker bearings a medium blow to align parts before checking fit.

If end of rocker that bears against end of valve stem is worn, dress down on emery wheel to regain original contour. Compare with unused part for correct shape.

REPLACING VALVE GUIDES

Replacing valve guides (24, Fig. 3B-1) 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.