Before assembling gear train, determine amount of end play in breather gear as follows: Assemble breather gear and dry cover gasket to gearcase. Select spacer washer (use washer disassembled unless it is known to give incorrect spacing) and position on end of breather gear. Place a steel straightedge across gearcase at spacer. With thickness gauge, measure distance between straightedge and spacer. Subtract .006 in. (amount gasket will compress) from this figure to determine gear end play. An end play tolerance of .001 to .005 in. is correct. If end play exceeds maximum, insert thicker spacer. Breather valve and gear spacer washers are available .115, .120 and .125 in. thick.

Establish proper cam gear end play as follows: Install thrust washer, spacing washer and cam gear. Position cover gasket and secure cover with at least four screws. Measure cam shaft end play between cam gear and cover bushing with thickness gauge through tappet guide hole in gearcase. End play should be from .u01 to .005 in. If measurement is under or over tolerance, remove cover and replace spacing washer with one to give suitable clearance. Cam gear spacing washers are available .050, .055, .060, .065 and .070 in. thick.

Make final gearcase assembly including all parts in approximate reverse of disassembly order. Breather, cam, pinion and intermediate gears contain timing marks which must be aligned or matched as shown in Fig. 3D-8. Rotate gear train and note if it revolves freely. A bind indicates gear are meshed too tightly. Make sure intermediate and idler gear spacers are assembled to their respective shafts.

Apply a coat of non-hardening gasket sealer to crankcase and cover gasket surface. Position new cover gasket and secure cover with all cover screws. Pour about 1/4 pint of engine oil over gears to provide initial lubrication before securing cover.

Assemble remainder of gearcase, generator and circuit breaker in reverse of order removed.

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