L84-85
(filter on the return part of the oil system)

L84-85 Oil Filter Pad 1)	Thread sizes. 2)

86-90:
(filter on the feed part of the oil system)

86-90 Oil Filter Pad 3)	Thread sizes. 4)

L84-85
Filter adapter (33115-79):
The oil filter adapter threads are the same size from L84-90.
Both ends have the same I.D. with a single hole drilled straight through.
The check valve in 85 and prior models is in the oil pump.
Therefore, the filter adapter is not set up for the check valve.

L84-85 Oil Filter Adapter. Each end has the same ID. Should work fine with a check ball and spring. 5)

86-90:
Filter adapter (33116-86):
Both ends have different I.D.s for use with either a check valve or a check ball.

86-90 Oil Filter Adapter: Each end has a different ID. Installs with larger I.D. outward 6)