S&S Cycle Super Stock and Special Application Crankcases for 1936-99 Big Twin Engines - Manual (Page 7)

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D- Primary housing oil scavenge passage
Location: Hole D. See Pictures 5 & 6.
1965 - early 1984 engines with dry clutch and engine supplied primary chain oiling.
Hardware: 31-2019 primary oil return fitting and 50-8331 socket head pipe plug. See Line Drawing, items 32 & 34.
Function: Hole D leads to vacuum side of crankcase breather gear. Hole D is normally used to scavenge oil from primary chain case in 1965
- early 1984 models with dry clutch and engine-supplied primary oiling.
Installation: 1965 - early 1984 engines with dry clutch and engine-supplied primary chain oiling only.
1- Install fitting 31-2019 in hole D.
2- Connect fitting 31-2019 to oil scavenge fitting on bottom of primary chain case with 3⁄8” hose.
Installation: 1980 to present engines with primary belt drive or sealed primary and wet clutch.
1- Install 50-8331 1⁄8 -27 pipe plug in hole D.
NOTES:
Plug Hole D with 50-8331 1⁄8-27 pipe plug if primary belt drive is used.
•
Hole D and fitting 31-2019 may be used to return top end oil in engines equipped with external oil return lines. Connect oil return lines from front and
•
rear cylinder heads with “T” fitting. Install fitting S&S® 31-2019 in hole D and route remaining line from “T” to this fitting. Breather gear will draw oil from
heads into gear case where oil pump can return it to oil tank.
E- Crankcase vent (breather) passage
Location: Hole E. See Pictures 3, 4, 5 & 6.
Hardware: 31-2020 rear chain “T” oil fitting, 50-8113 45° hose fitting, or 50-8331 socket head pipe plugs. See Line Drawing, items 33, 34, 35.
Function: Vents crankcase to atmospheric pressure. Also used to oil rear drive chain in some models.
Installation: 1936 to 1964 models with crankcase breather stud.
Plug hole E with 50-8331 1⁄8 -27 socket head pipe plug. Do not overtighten.
Installation: 1965 to 1969 models
1- If separate breather and rear chain oiler are to be used:
a- Install 50-8113 45° 1⁄4” pipe x 3⁄8” hose fitting (See Line Drawing, item 33) in hole E.
b- Connect 3⁄8” ID. hose to 50-8113 fitting. Route 3⁄8” hose down toward ground or to rear chain. Avoid brake and tire surfaces because oil-
air mist exits hose. Hose may also be routed to carburetor air cleaner if desired or required by local emission standards.
c- Connect rear chain oiler line to rear chain oiler fitting on stock oil pump or S&S oil pump. Avoid brake and tire surfaces because oil-air
mist exits hose.
Oil on tires or brakes may cause loss of control of motorcycle resulting in serious injury to operator and others.
2- If room allows, breather t-fitting 31-2020 (See Line Drawing, item 37) may be installed in hole E. Follow directions below for 1970 to 1979
models.
NOTE: Installation of 31-2020 fitting may not be possible on chassis with mechanical rear brakes due to clearance problems.
Installation: 1970 to 1979 models with rear chain oiler.
1- Install fitting 31-2020 in hole E.
2- Connect 3⁄16” ID. hose from rear chain oiler fitting on oil pump to small “T” hose nipple on 31-2020 fitting. See Picture 10.
3- Connect 3⁄8” ID. hose to large hose nipple on 31-2020 fitting. Route 3⁄8” hose to rear drive chain.
WARNING
Picture 10