See also 97 Oil Pump (26204-91) Parts (approximate) Dims
More on the Evo Sportster Oiling System in the Sportsterpedia.

Oil is routed from the oil pump into the oil filter pad and then into a horizontal feed galley in the top of the gearcase.
The oil pump has one feed fitting in the front routed to the filter pad.

91-97 oil path from pump 1)	Parts list 2)

There are 2 versions of this pump although the catalog part number did not change.
The 91-96 version has pump body casting p/n in 26485-90 in the return cavity and pump cover casting p/n 26487-90.
The 97 version has pump body casting p/n in 26485-90A in the return cavity and pump cover casting p/n 26487-90A.

The separator plate, thrust washer, retaining ring and both feed and gerotor sets are identical in each version.
The gear dims are also the same.
However, the gearshaft in the -90A pump is .005“ longer than the one in the -90 pump.
The gearshaft for the -90A pump can be identified by having six hash marks across the top of the gear.

There are two different gearshafts used for the two different pump casting numbers even though the catalog part # stayed the same.
Visually, they are identical.
However, the gearshaft used in the pump with bottom casting # 26487-90A is .005” longer and has six hash marks across the top of the gear to distinguish it.

The 91 and up oil pumps only have 1 separator plate.