Harley Davidson military motorcycle model 42 WLA-solo (civilian models WL & G 1940-1952). Operation and maintenance manual — page 2

Servicing Air Cleaner

With motorcycle in normal use on hard-surfaced roads, clean and refill air cleaner oil cup at least each time engine oil tank is drained and refilled. Service more frequently under dusty conditions; daily under extremely dusty conditions.

To service round type cleaner:

Loosen oil cup clamp band thumb screw, remove oil cup and baffle, thoroughly wash and clean oil cup and baffle and refill oil cup to indicated oil level with same grade of new oil used in engine.

In reassembling, observe that oil cup gasket is in place and be sure oil cup and baffle are properly seated against gasket and secured to cleaner housing. Careless assembly is likely to result in an oil and air leak between cup and cleaner housing and possibly a lost cup.

Occasionally, at time of servicing oil cup, complete cleaner should be removed from motorcycle and immersed for a time in a bucket of gasoline or kerosene (or available solvent). Cleaner element, which cannot be removed from housing, must be thoroughly flushed to wash out accumulated dirt. After flushing dry thoroughly (use an air hose if available) and apply a few squirts of engine oil to inside of cleaner element, using oil can.

when fully closed. Also, passage around valve when fully open is somewhat restricted. To correct this condition, additional clearance will need to be cut above cylinder seat so top edges of angular valve face and cylinder seat match exactly. This is illustrated on Page 38, Illustration 27.

If seat is refaced with a cutter it will not be as smooth as when refaced with a grinder and a greater amount of lapping will be necessary to attain a perfect seat.

When a new valve guide is installed, it is not likely to have exactly the same relation that the old guide had to valve seat. Therefore, it is especially important, after fitting new guides, that seats be carefully refaced to make them concentric with guides and assure perfect alignment and matching of valve face and valve seat.