Pump Changes

It is not necessary to remove complete oil tdubid from engine in order to make these changes. Refer to 1948 Big Twin warts catklog, page 23. Remove pump cover and governor rotor part Nos. 682-41 and 687-41C, and also remove cover plate Np.

683-41. Discard governor rotor and cover pl.-te. Install new cover plate 683-49.

You will note that new cover plate blocks off the holes in pump body and cover that formerly passed oil to and from the governor. (If a new cover nlate 683-^9

is not available when it is desired to make this pump change, use the original plate after securely plugging these holes. After plate and gasket are installed replace pump cover.

Remove and discard pump check valve spring 703-b8, md replace it with check valve spring 703-36$ which is a much lighter spring. 703-36 is the same chock valve spring used, in I9U7 and earlier oil pumps.

With, the above described changes made in the oil primp, oil pressure builds up much faster from low speed, and considerable more oil is circulated through ongine while idling and operating in the low speed range. This explains the ring change from a moderate to a vented oil control ring.

7. When servicing as. engine as outlined above, if piston rings were found badly worn and scuffed, and cylinder walls also scratched and scuffed, don't fail to thoroughly flush out engine base, timing gear case, and oil tank before reassembling and putting engine back in service. Where there is undue piston and cylinder wear, the engine oil becomes contaminated with fine particles of metal, Unless a newly serviced engine is put back in use with clean, fresh oil, free of metal particles a.nd other contamination, undue wear is again likely to be experienced, 3ver, an engine that appears quite clean, snd with little, if any ring and cylinder boro wear, should at least have the oil tank drained, flushed, and refilled with fresh oil before putting: back in use. jjrj

S. When-.-reassembling cylinders and heads, apply gasket sealer to all gaskets. If the head cover gaskets you have available are only about 1/32" thick, use two per head, if approximately 3/GU" thick use only one gasket. Only the later ^I'c'A" thick cover gasket is now used in new production and supplied on parts order.

9. Install spark plugs with the latest 7/8" outside diameter plug gasket, especially if there has been seepage of oil between cylinder head and spark plug insert, 'The new larger gasket will seal any leakage at this point, as it is large enough to overlan the insert and seal against head surface. Gasket nart No. 323U2-U2.

Order needed oil punro conversion kits (new cover plate and check valve spring) under Part No, This kit will be furnished no charge. Order only a few at a time as needed for short period requirements, as at present these parts are available in limited quantity┬╗

While all of the later 19*+g O.H.V. engines wore fitted with four rings per piston, a few of the last O.n.V.'s shipped at the end of the ijg season, had oil pump converted. A list giving the number of those motorcycles is attached hereto.

It is also permissible in the case of any I9U8 O.K.V. engine that is running normal or above normal oil mileage to convert oil punro. If, however, an engine is already over oiling as Evidenced by low oil mile-age, heavy exhaust smoke, and plug fouling, Just converting the oil pump but doing nothing else is likely to make matters worse. When an engine is already over oiling through combustion chambers, it should bo serviced as outlined above before converting oil pump.

0 0

Post a comment