Having re-assembled the flywheels in the crankcase and bolted the two halves of the case together, it is necessary to fit the crankshaft bevel gear into place, making certain that the keyway slot in the gear is engaged with the key in the mainshaft, and that any spacing shims originally fitted are put back or replaced with new shims of similar thickness. Tap the gear firmly home and then fit the bottom bevel bush housing and vertical bevel into position with the same number of joint washers between the face joints as were used originally. Fit the washers and nuts on to the studs and tighten down carefully.

The aim is to get the bevels meshing for the full width of the teeth without backlash but with perfect freedom from tightness in all positions. If the pinions when checked are too slack remove them and take out a joint washer from the bush housing or fit an additional shim behind the crankshaft pinion. Re-assemble and check them again. Tight meshing can be rectified by fitting additional paper packings under the face of the vertical bevel bush housing or removing shims from behind the crankcase pinion.

The whole procedure is difficult to describe adequately, and some skill is needed to make a good job, but by careful selection of the correct thicknesses of shims and joint washers final correct setting can be achieved.

When meshed correctly remove the bevel bush housing, coat the face joints with good jointing compound and re-assemble, tightening the two nuts down carefully.

Fit the magneto driving gear in place on the shaft and tap it up into position. Follow it up with the small tongue washer and fit the ball valve spring into the end of the mainshaft. Stick the ¼-in. bearing ball into the left-hand thread nut with a light smear of soft clean grease and screw up the nut tight.

Finally fit the magneto chain case and timing cover with the magneto, magneto chain, sprockets, and bottom spindle and gear in place. See that the coupling is fitted on to the projection of the oil pump spindle.

It may be a little difficult to get the "Half time" gears meshed and coupling engaged with the recesses in the gear, but after one or two attempts success should be achieved.

A new joint washer (K68/3) should be provided and the face joints cleaned carefully and lightly smeared with jointing compound. Tighten the screws carefully and evenly. It is specially advised that the engine should not be started until the magneto chain cover is fitted and all screws tightened, otherwise the oil pressure in the bottom bevel housing may burst the timing cover joint.