Warning – S&S Cycle Crankcase Breather Stud Assembly User Manual

Page 2

The S&S

crankcase breather stud assembly is a replacement

unit for 1948-'57 and 1964 Harley-Davidson

motorcycles with

lost oil primary chain drive systems. It is a replacement for H-D

#24912-48 and is compatible with all S&S Generator Crankcases
except those manufactured to 1965-1969 specifications.

Note: All reference to Harley-Davidson

part numbers is for

identification purposes only. We in no way are implying that any
of S&S

Cycle’s products are original equipment parts or that they

are equivalent to the corresponding Harley-Davidson

part

number shown.

NOTE: S&S breather stud assembly may be used on most other
big twins manufactured before 1965 if a

⁄

” hole is drilled in inner

primary cover. Many aftermarket inner primary covers have this
hole and accept S&S breather stud without modification.

Please familiarize yourself with the kit contents and
installation instructions before proceeding. A Harley-Davidson

Service Manual for the correct year and model should be
referred to as necessary.

Contents:
Part 106-4795 - S&S Crankcase Breather Stud Assembly

Spigot, Crankcase Breather Stud . . . . . . . . . . . . . . .106-4900

Deflector, Front Chain Oil (H-D

#24932-39) . . . .31-2038OP

Screw, Hex head,

⁄

-18 x 6

⁄

”

(Case Breather Stud) . . . . . . . . . . . . . . . . . . . . . . . . . . .50-0103

Clamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50-8002

Washer, Flat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50-7034

INSTALLATION
1. Remove outer primary cover, noting position of breather

stud spigot and oil deflector assembly in relation to
primary chain.

NOTE: Breather stud is located at approximately eight o’clock
position as viewed from right or cam side of engine. Harley-
Davidson

Service Manual should be consulted for correct

position of spigot and deflector in scratch build applications.

2. Remove primary drive assembly and inner primary cover.

NOTE: OEM breather stud may utilize metal or rubber oil
deflector. If metal, deflector must be removed from spigot before
inner primary cover can be removed. Clean both sides of
crankcase around breather stud. Remove nut from old breather
stud and remove stud from left side of engine.

3. Fit flat washer provided in kit over 6

⁄

” bolt. Apply

Loctite

242 (blue) or equivalent to bolt threads. If desired,

place thin bead of silicone or preferred sealant around edge
of spigot that contacts crankcase and allow to cure per
manufacturer’s instructions.

4. Place spigot in same position as item removed in Step 1,

insert bolt through crankcase from right side and
tighten securely.

NOTE: Knucklehead drive side crankcases have locating pin that
must engage dimple in spigot. Pin will position spigot for proper
lubrication of chain. Panhead cases do not have pin. In panhead
applications spigot must be installed in same position as original
elbow noted in Step 1. Refer to Service Manual as necessary.

5. Install inner primary cover and primary drive.

NOTE: Breather opening in some inner primary covers may not
align with S&S breather spigot. In such instances, hole may be
cut in correct location using properly positioned breather
spigot as guide.

Adjust chain according to Service Manual. Position oil
deflector on elbow so as to direct air-oil mist to chain. Secure
elbow with provided clamp.

7. Remove spark plugs and rotate engine several revolutions

while observing movement of primary chain to confirm
adequate clearance between chain and breather deflector.
Install outer primary cover and spark plugs.

Incorrectly installed oil deflector could loosen and lodge
between chain and sprocket, causing damage to parts
involved and possible loss of control of motorcycle with
resulting personal injury or death to operator and others.

8. Observe primary chain for proper lubrication after 50-100

miles. Adjust and retighten deflector clamp as needed.

Picture 1

WARNING