IH: Engine Mechanicals

See also Crankshaft / Flywheel Tools in the Reference section of the Sportsterpedia.

Sub-Documents

Motor Mounts

Click here for Engine Mounts in the Sportsterpedia.

Timing Hole Plug

Click Here to go the Timing Inspection Hole and Plug - Sealing and Thread Repair page in the Sportsterpedia.

1954-1971 KH / Sportster Timing Hole Plug (704).
This plug was also used as an oil tank drain plug for 1958-1961, 1966-1978 XLCH and 1979-1981 XLH, XLCH, XLS Sportsters.
Threads: 5/8“-18 x 3/8” with 3/4“ Hex Head.

Click on a pic to enlarge:

1) 2)


1972-2003 Sportster Timing Hole Plug (720).
Threads: 5/8”-18 x .350“ with 3/8” Hex Socket (Allen) Head.

3) 4)

Primary Cover

Primary Cover Gaskets

Below is a list of factory gaskets used on Sportster primary covers.
Pics of the different part numbers are listed to the right in the chart. Click on the link to open a picture of the part.

Year ModelPart#NotesPics
1952-1953 K Model
1958-1969 XLC, XLCH
34955-52XLCH “Tin” cover gasket. Kickstart only.
Can also replace XLH gasket 34955-52A.
Pic 5)
1954-1956 K Model
1957-1966 XL/XLH
34955-52AXLH aluminum cover gasket. Kickstart only.Pic 6)
1967-1976 XLH
1970-1976 XLCH
34955-67First electric start XL motor.Pic 7)
1977-1985 XLH
1977-1979 XLCH
1983-1990 Sportster
34955-75
1980-1982 XLS34966-80Same exact gasket as 1977-1985 version above, just black in color.

Shifter Shaft Bushing

1977-2003 Bushing

1977-2003 Sportster Primary Cover Shifter Shaft Bushing 40520-63. Bushing is open ended.
Below are approximate (only) dims. 8)



Primary Cover Dowel Bushing (1977-1985)

Dowel bushing part# (24754-77).
1977-1985 covers used 3 dowel bushings to locate the primary cover to the left case. (same bushing used through 1996 covers)
The mounting bolt hole in the cover is drilled for the OD of the bushing with the ID of the bushing sized for the mounting bolt.

9)

Name Transfer (1971-1980)

These are used in the “pocket” in the center of the primary cover.
1971 XLH, XLCH used the transfer labeled “900” (34960-71).
1972-1976 XLH, XLCH used the transfer labeled “1000” (34960-72).
1977-1978 XLCR used the transfer labeled “CR1000” (34965-77).
1977-1980 XLH, XLCH used the transfer labeled “Sportster” (34961-77).
1979-1980 XLS used the transfer labeled “1000” (34962-79).

10) 11)

12)

Access Covers / Cap Plugs

1957-1970 XL/XLH and 1970 XLCH

Oil Filler Hole Plug (34742-52A):
The plug cap is threaded for removal to add oil to the primary case.
The plug is polished and knurled with a small hole through the center and filter mesh staked in place on the inward side of the plug.
It screws into the hole in the primary cover with no seal. The small hole with filter mesh serves as primary air intake.
This hole allows air to come into the primary replacing what's lost to the crankcase from the transfer valve in the left case half.
It also serves to control the amount of vacuum built up in the primary case by way of intake air from outside the case.
The plug has a slot milled out across the face as a socket for removal/installation and the tool is similar to and fits into the slot.

1957-1970 XL/XLH and 1970 XLCH Oil Filler Hole Plug (34742-52A) 13)

1971-1976 All Models

Oil Filler Hole Plug (34742-71):
Changes made to the 57-70 hole plug include no knurling and now using a sealing O-ring (11106).
The plug cap is threaded for removal to add oil to the primary case.
The plug has a small hole through the center and filter mesh staked in place on the inward side of the plug.
It screws into the hole in the primary cover and seals with the installed O-ring. The small hole with filter mesh serves as primary air intake.
This hole allows air to come into the primary replacing what's lost to the crankcase from the transfer valve in the left case half.
It also serves to control the amount of vacuum built up in the primary case from outside air intake.
The plug has a slot milled out across the face as a socket for removal/installation and the tool is similar to and fits into the slot.

Clutch Adjustment Hole Plug (37880-71):
This cap plug was introduced on the primary cover with the redesigned wet clutch models and installs over the clutch adjuster.
The procedure for clutch cable adjustment (as outlined in 1971-1972 Sportster owner and FSMs require the removal of the chain cover.
The MoCo revealed an easier way to make clutch adjustments by removing the access plug from the chain cover instead of removing the cover.
Click Here to go to the service bulletin page and scroll down to TSB #634 to view that PDF bulletin.
The cap plug is polished, has knurled edges and doesn't install flush with the cover.
The clutch adjustment hole plug also uses O-ring (11106), has no through-hole vent and has overlapping slots cut into the face in a “cross” pattern.
No vent is needed in this cap since the oil filler plug has the vent controlling air intake.

1971-1976 Sportster Primary Oil Filler Plug (34742-71) 14)
1971-1976 Sportster Clutch Adjustment Hole Plug (37880-71) 15)

1977-1985 All Models

1977-1985 models use 2 identical hole plugs for the oil filler hole and the clutch adjustment hole.
It's looks the same as the 1971-1976 oil filler hole plug but it has no vent hole.
The primary now breathes from a rubber hose on the top rear of the transmission.
The plug went through a couple revisions but any of these will fit and function on 1977-1985 primary covers.
1977 models used (34742-77)
1978-E1985 models used (34742-77A)
L1984-1985 models used (34742-77B)

L1984-1985 Primary Oil Filler Plug 34742-77B 16)

Gearcase / Cam Chest Cover

Cam Cover Gasket

Make sure to use the correct gasket for your engine/cover specifics.
There were changes to the upper feed galley that dictate a specific gasket, especially between 1979-1982 models.
The upper oil feed galley was redesigned during the 1979-1982 and according to the MoCo, the gasket must fit the case design.

Below is a quick list of factory gaskets used on Sportster gearcase/cam covers.
Pics of the different part numbers are listed to the right in the chart. Click on the link to open a picture of the part.

Year ModelPart#Notes
1952-1976 K Models, Sportsters25224-52See below
1977-some E1981 Sportsters25224-52A
1982-1985 Sportsters
(some 1981 Sportsters)
25263-81


More in depth information on the right case changes that affected the cover gasket from 1979-1982;
Click Here to read more about gearcase changes around the upper feed galley.

1957-E1982 right cases with the small boss and upper oil feed oil slot:
1952-1976 K and Sportster original gasket (25224-52), designed with an upper feed oil hole. Updated gasket (25224-52A).
1977-L1981 and some E1982 Sportsters original gasket (25224-52A) original had a single for the upper feed galley passage.
The original gasket was updated in Nov. 1979 with a short slanted slot added to match the gearcase modification in L1979-E1980 models. 17)
And the updated -52A gasket replaced the -52 gasket for 1952-1976 models in the -78B catalog.

1982-1985 and some L1981 right cases with the large boss and upper oil feed hole:
L1981-1985 Sportsters use gasket (25263-81), designed with a long horizontal slot.

1957-E1982 oil feed slot 18) L1981-1985 oil feed hole 19)
Cam Cover Gasket (25224-52A) 20) Cam Cover Gasket (25263-81)

Cam Cover Bushings

Pinion shaft bushings

1952-1976 bushing (25593-57) uses a .625“ pinion bushing bore. 21)
1977-2020 bushing (25593-74) uses a .562” pinion bushing bore.

Oil Deflector / Separator Bushing Assembly (1957-1962)

AKA, (spring loaded top hat)

Looking at the brass part, you can see how the spring catches on the inward bent tabs. There are also unbent tabs on the brass. 22)
These, when bent outward just a little, fit into slots on the far side of the steel bushing pressed into cam cover.
Here's how the factory assembled this thing.
They had pre-assembled the brass to the steel before the steel was pressed into the cover.
Then dropped the spring into the cover and pressed the brass/steel assembly into the cover as a unit (and manipulated the spring to sit correctly if needed).
However, it is possible to assemble the unit without removing the steel from the cover. 23)
You can bend the tangs out without having to remove the steel bush with a screwdriver and a hammer to bend the 2 locating tabs out.
Notes:
The tabs must be bent outward enough that the brass stays keyed to the steel at full spring compression.
You don't want the brass hat to 'unkey' when the generator compresses spring. The brass needs to be able to 'plunge' in and out under the spring pressure once the tags are bent.
If you get too aggressive, you can cause deformations in the brass that allow it to hang up in it's sliding fit to the steel.
These outward bent tangs do 2 things.

  • They keep the brass hat and spring captive in the cover upon generator removal.
  • More importantly, they key the brass to the steel to prevent the brass from rotating with the generator gear.
    The brass is unable to rotate by the tangs keying into the slots.

Inspection:
Check the operation of the oil separator bushing assembly.
The spring should have free action and be fully extended in the gearcase cover.

24) 25) 26)

27) 28) 29)

Shifter Shaft / Brake Shaft Hole Bushings and Plugs

1952-1974 Cam Covers:
1952-1974 K models and Sportster use shifter shaft bushing (34037-52) in both the right case and the cam cover.
This bushing is open ended for the long shift shaft to run through it.
Bushing (34037-52) App. Dims:
Bushing OD: 5/8“
Bushing ID: 1/2”
Bushing Length: 3/4“

1975-1976 Cam Covers:
1975-1976 Sportsters use shifter shaft bushing (34037-52) in the right case and bushing (34037-75) in the cam cover.
As result of the Sportster going left side shift in 1975, the shifter shaft got shorter out of the right case.
The shaft end has linkages back to a crossover arm through the frame.
This bushing has one closed end which is installed on the outside of the cover.
Bushing (34037-75) App. Dims:
Bushing OD: 5/8”
Bushing ID: 1/2“
Bushing Length: 3/4”

1977-E1981 Cam Covers:
1977-E1981 cam covers came with a different bushing (25594-75) for a brake shaft.
Starting in 1977, the shifter shaft exits out the left case and the old then shifter shaft location in the cam cover became the brake shaft location.
This was the brake shaft design from 1977-1979 (even though the rear brakes went hydraulic in 1979).
However, in 1980, the MoCo moved the brake operating lever to the trans sprocket cover so the hole in the cam cover was now useless (1980-1985).
Cam Cover Bushing Bore: .7450“ 30)
Bushing (25594-75) App. Dims:
Bushing OD (before installing): .752” 31)
Bushing ID (before installing): .6250“ 32)
Bushing Length: .625” 33)

1980-E1981 Cam Covers:
In 1980, the MoCo used a rubber plug (25221-77) in the now unused brake shaft hole in the cam cover.
The brake shaft bushing was still installed presumably to allow later covers to be used on 1979 models.
The rubber plug inserts into the bushing.
The parts books (1980-1985) show the rubber plug sold for 1979-E1981 Sportsters.
As usual, that means they expected one to upgrade the 1979 system to the 1980 system.

L1981-E1984 Cam Covers:
Once again a change was made in “how to plug a hole that goes nowhere”.
There may have been some problems with the rubber plug falling out or other. The bushing and plug was deleted from the cover.
The hole was still there but threaded for metal plug (2506), 7/16“-14 x 1/2” hex socket bolt, which screws into the cam cover.
L-1984-1985 covers did not use a plug nor did they have a hole for a plug even though the parts books show the plug for L81-85 models.

1975-1976 Sportster cam cover shifter shaft bushing: 34)

1977-E1981 Sportster cam cover brake shaft bushing: 35)

1977-1978 XLCR, 1979-E1981 cam cover brake shaft hole rubber plug: 36)

L1981-E1984 Sportster cam cover screw plug: 37)

Ignition Timer Cover

38)

Parts Lists

Engine Cases

All part numbers were gathered from period specific Sportster parts catalogs from 1957-1985 including supplement and updated catalogs.

Year ModelCase Set
Part#
Left Case
Part#
Left Case
Casting#
Right Case
Part#
Right Case
Casting#
1957-1965 XL/XLH24511-5724532-5724534-5724556-5724558-57
Notes“No hump” cases (primary not cast for electric start)
1958-1965 XLC/XLCH24515-5824532-5824534-5724556-5724558-57
Notes“No hump” cases (primary not cast for electric start).
1966 XLH24511-57
24511-57A
24532-5724534-5724555-57
24555-57A
24558-57
Notes “No hump” cases (primary not cast for electric start).
E1966 case set (24511-57) replaced by (24511-57A) on 1-13-1966
Factory changes made starting with crankcase# (66 XLCH 6117-up); 39)
Right case has fillet added to base of countershaft low gear boss.
Right case is replacement for all 1957-1965 models.
-57A case set is replacement for 57-66 XL/XLH (24511-57)
Left case is replacement for 1957-1966 XL/XLH
Case set (24511-57A) replaced by 1969 XLCH case set (24515-58A) in 1969
Left case replaced by XLCH (24532-58) in 1969 for 57-66 XL/XLH
1966-1969 XLCH24515-58
24515-58A
24532-5824534-5724555-57
24555-57A
24558-57
Notes“No hump” cases (primary not cast for electric start).
E1966 case set (24515-58) replaced by (24515-58A) on 1-13-1966
Factory changes made (66 XLCH 6117-up); 40)
Right case has fillet added to base of countershaft low gear boss.
-57A right case is replacement for all 1957-1965 models
-58A case set is replacement for 1966 XLH in 1969
1967-1968 XLH24512-6724531-6734-6724555-6724558-67
Notes“Hump” cases (primary cast to accept electric starter)
1969 XLH24512-67A24532-5834-6724555-67A24558-67
Notes“Hump” cases (primary cast to accept electric starter).
Right case is replacement for 1967-1968 XLH
Case set is also replacement for 1967-1969 XLH
Right case, lower left of gearcase, drilled and tapped for chain oiler fitting.
L1969-E1971 XLH/XLCH24512-67A24531-6734-6724555-67A24558-67
Notes1970 and all future Sportster year cases are “hump” cases for electric start
Left case is replacement for 1967-1969 XLH
Right case is replacement for 1967-1969 XLH
Case set is also replacement for 1967-1969 XLH
1978 parts supplement corrects “used on” models to 70-71 XLCH
VIN moved the from the left side case to the right case.
A blank Vin pad is still on the left with no number stamped on it. 41)
L1971 XLCH24512-7024531-67 24555-7024558-67
NotesCase set is also replacement for 1970 XLCH.
1972 XLH/XLCH24505-7224535-7224534-7224551-7224558-72
NotesFirst year for 1000 Sportsters. Last year of the speedometer drive gear in the right case.
1973-1976 XLH/XLCH24505-7324535-7324534-7224551-7324558-73A
NotesThere was a late 1973 cylinder and head change but the crankcase was left unchanged 42)
Starting in 1976, case halves not sold separately
1977-1978 XL/XLCH/XLCR24527-75 - 24534-75 - 24558-75
NotesCases redesigned for a minisump, new oil pump mounting boss, left side shifter
Crankcase breathes thru holes in gearcase wall, oil trough for timed breather deleted.
Vertical oil scavenge passage drilled in sump wall
1979 XL/XLCH24527-75A - 24534-75 - 24558-75
NotesRight case modified to eliminate high pressure oil leakage around the oil passage between the
upper crankcase cover and crankcase in November, 1979 43)
1979-1980 XLS24490-79A - 24534-75 - 24558-75
NotesLast year cases were cast with hole for kick start.
1980 XL24527-75B - 24534-75 - 24558-75
NotesCase set is also replacement for 1979 XL/XLCH.
1981-1982 XL24527-81A - 24534-81 - 24558-75A
NotesSold for 1982-E1984 XL/XLS/XLX in 1985
Must use rear motor mount 16203-82A
L1981 to E1982 production change on the right case, all XL models.
On some cases, the oil galley slot in the top of the gearcase was not machined.
Instead, a hole was drilled thru to connect the oil path.
Upper left corner of gearcase also received additional threaded hole to mount the gearcase cover.
Left case has a new “hump” casting to mount the new Nippon Denso starter.
1981-1982 XLS24490-81A - 24534-81 - 24558-75B
NotesCase set is (painted black). See 1981-1982 XL production change above.
1981-1982 XLS
replacement
24490-81C - -
NotesReplacement (painted black) case for 1981-1982 XLS offered in 1983
Must use rear motor mount 16203-67A on 1981 models
Must use rear motor mount 16203-82A on 1982 and 1983 models
1982 XLS
replacement
24490-82 - -
NotesReplacement (painted black) case for 1982 XLS offered in 1984
Must use rear motor mount 16203-82A
1983 XL/XLS24527-81C - 24534-83 - 24558-83A
NotesReplacement case for 1981-1982 XL offered in 1983
Must use rear motor mount 16203-67A on 1981 models
See TSB M-876A for more details
Must use rear motor mount 16203-82A on 1982 and 1983 models
L1983 production change:
The roll pin for the trans thrust washer in the case was removed. 44)
L1983 XR-100024517-83 - -
Notes
E1984 XL/XLS/XLX24480-84 - 24534-83A - 24558-83B
NotesCase set 24480-84 is listed in 1984 parts book but number was later given to L1984 case set 45)
E1984 XL/XLS/XLX24527-82A - 24534-83A - 24558-83B
NotesLate 1984 production change 46)
Case set is also replacement for 82-E84 models
Must use rear motor mount 16203-82A
New crankcase set starting with crankcase date code 7 84 174011 (June 22, 1984).
Features new mainshaft bearing race (35105-83) and new pressed in mainshaft seal (12049).
Trans mainshaft/roller bearing/retaining ring remain unchanged
Same channel cast into right side of tranny compartment but hole not drilled for stator grommet
L1984 XL/XLS/XLX24480-84 - 24534-83A - 24558-83B
NotesProduction change in 1984
Generator deleted, hole in case there redesigned for oil filter mount
Stator mounted to trap door w/ hole in case for wire grommet
Channel cast into right side of tranny compartment ending in hole for stator wire grommet
1985 XL/XLS/XLX24480-85 - -
NotesOriginally listed for all 1985 models thru the -85 parts book
Sold for Late 1985 thru the -85A parts book
Starting with crankcase# (785 303002) a cam gear oiler was installed
Right case drilled/tapped between F-R tappets for oiler tube feed oil
Gearcase wall tapped to attach oiler tube
E1985 XL/XLS/XLX24480-85A - 24534-83A - 24558-83B
NotesSold for Early 1985 thru the -85A parts book

Flywheels

All part numbers were gathered from period specific Sportster parts catalogs from 1957-1985 including supplement and updated catalogs.

Year Model →
Parts ↓
1952-1953
K/KK
1954-1956
K Models
1957-1971
XL/XLH
XLC/XLCH
1972-1976
XLH/XLCH
1977-1979
XLH/XLCH/XLS
full assembly
used until
depleted →
1980-E1981
XL / XLS
full assembly
used until
depleted →
L1981-1985
XL/XLS/XLX
Flywheel Assembly
w/shafts, w/rods
23900-5223900-54
23900-54A
23900-57
23900-57A (72)
23900-57A23900-7523900-75A23900-75B
23900-75C (83)
Left
Flywheel
23915-5223916-54
23916-54A
23916-57
23916-57A (72)
23916-57A23916-57A
Keyway
23916-57A23916-80
No keyway
Right
Flywheel
23935-5223936-54
23936-54A
23936-57
23936-57A (72)
23936-57A23936-57A
Compound
oil path
23936-57A
timing marks
changed
from case#
780-108-001 47)
23936-80
Single line
oil path
Connecting Rod
Assembly
w/bearings
w/crankpin
24275-5224275-5424275-5724275-5724275-5724275-5724275-80
Rear
Rod
24290-5224290-5224290-5724290-5724290-5724290-5724290-57
Front
Rod
24294-5224294-5224294-5224294-5224294-5224294-5224294-52
Crankpin23960-5223960-5423960-5423960-5423960-54
Oil hole 110°
from keyway
23960-5423960-80
w/ plug
Oil hole 90°
from keyway
Crankpin
Roller (std)
(1 roller)
9101 (E52)
9381 (L52-53)
9401 (52-53)
9441
9441A (59)
9150
9150A (59)
9441
9441A (59)
9150
9150A (59)
9441A
9150A
9441A
9150A
9441A
9150A
9441A
9150A
Crankpin Key23985-18
1/8“ x 1/2”
23985-18
1/8“ x 1/2”
23985-18
1/8“ x 1/2”
23985-18
1/8“ x 1/2”
23985-18
1/8“ x 1/2”
23985-18
1/8“ x 1/2”
11218
1/8“ x 3/8”
Crankpin Boss
Washer
23972-5223972-5423972-5723972-7223972-72 (E79)
6506 (L79)
65066506
Crankpin Nut23967-4823967-5423967-54
23967-54A (71)
23967-54A23967-54A
Crankpin Nut
Lock Plate
24015-3624015-36 (E54)
23971-41 (L54)
23971-4123971-4123971-41
Lock Plate
Screw
266926691187 48)
2669 49)
2669W (65)
2669W
Con Rod Rear
Roller Retainer
24362-52
24361-54
24362-5424362-5424362-54A24362-54A24362-54A24362-54A
Con Rod Front
Roller Retainer
24364-52
24361-54
24364-5424364-5424364-54A24364-54A24364-54A24364-54A
Con Rod Rear
Bearing Race
24341-52A (74)24341-52A (74)24341-52A24341-52A24341-52A
Con Rod Front
Bearing Race
24352-52A (74)24352-52A (74)24352-52A (74)24352-52A24352-52A24352-52A
Sprocket Shaft24000-5224000-5424000-5724000-5724000-7524000-75
Large keyway
24000-80 50)
24000-81 51)
common taper
No keyway
Sprocket Shaft Key23985-12
3/16“ x 1/2”
23985-12
E54 KH
40390-54
L54-56
40390-5423985-12
3/16“ x 1/2”
23985-12
3/16“ x 1/2”
23985-12
3/16“ x 1/2”
not used
Gear Shaft24005-5224005-5424005-5724005-5724008-75
-77A, -78
3/16“ key
24008-75A
2-piece 52)
24005-75 53)
24005-80 54)
1-piece 55)
common taper
1/8” key
Gear Shaft Key23985-18
1/8“ x 1/2”
23985-18
1/8“ x 1/2”
23985-12
3/16“ x 1/2”
23985-12
3/16“ x 1/2”
23985-12 (E79)
11200 (L79)
11200 56)11218
1/8“ x 3/8”
Sprocket Shaft
or Gear Shaft
Lock Plate
24015-3624015-36
Lock Plate
Screw
266926691187 57)
2669 58)
2669W (65)
2669W
Sprocket or Gear
Shaft Nut
24003-54
(54-E55)
8011
(54-56)
8011801180118011
Pinion Gear Nut
Tabbed Washer
7913
7044
7913
7044

L1981-up Commonized Flywheels

  • In May of 1981, the MoCo issued a bulletin stating that product and quality improvements have brought about a commonized flywheel taper design.

All tapers were communized at 6° and all keyways were standardized. In June of 1981, an update to this bulletin was issued to include part numbers. 59) 60)

  • A limited number of E1982 XL engines (782216009-782237017) were assembled without the communized flywheel taper design. 61)
    • Notable component changes are included in the chart below.
    • This was a running change in 1340cc and 1000cc engines but both new and old designs were used in production until the old stock parts ran out.
    • Assembly and disassembly was the same for the old and new style flywheels but the torque values did change for the new style assembly.
      However, new and old style components must not be intermixed.

Changes for Sportster 1000 engines include:

New Flywheel -
Sprocket Side
Gear Side

23916-80
23936-80

'Lazy 8' rear cylinder timing mark and no keyway
Single hole oil path.
The old style flywheel has a keyway on the sprocket side (23916-57A) and a compound (2) hole oil path on the gear side (23936-57A).
New Crankpin23960-80Oil hole is now 90° to the keyway
Old style crankpin (23960-54) oil hole was 110° to the keyway
New Crankpin Nuts23901-8120/1“ thread pattern at 150-185 ft/lbs.
Old style crankpin nuts (23967-54A) were 20/1” threads with 150-175 ft/lbs.
New Sprocket Shaft24000-80No keyway
Old style sprocket shaft (24000-75) has a large keyway
New Sprocket Shaft Nut23902-813/4“ x 20 threads at 100-120 ft/lbs.
Old style sprocket shaft nut (8011) has 11/16” x 18 threads at 100-120 ft/lbs.
New Sprocket Shaft KeyNot used
Old style sprocket shaft key (23985-12) has a large woodruff key (3/16“ x 1/2”)
New Gear Shaft24005-80One piece construction
Old style gear shaft (24008-75A) is of two piece construction
New Gear Shaft Nut23902-813/4“ x 20 threads at 100-120 ft/lbs.
Old style gear shaft nut (8011) has 11/16” x 18 threads at 100-120 ft/lbs.
New Gear Shaft Key11218Small woodruff key (1/8“ x 3/8”)
Old style gear shaft key (11200) has a large woodruff key (3/16“ x 1/2”)
New Crank Key11218Small woodruff key (1/8“ x 3/8”)
Old style crank key (23985-18) has a large woodruff key (1/8“ x 1/2”)

Roller Bearing Inspection (1957-1976)

  • In a letter dated May 9, 1977, an HD interoffice memo was sent regarding an inspection of parts stock roller bearings. Some roller bearing part numbers were found to have incorrect diameters. A new micrometer was purchased to remedy this problem.
  • Two of those part numbers are gear shaft (9421) and crank pin front rollers (9150A) for Sportsters.
  • In light of this oversight, a listing of part numbers with their correct dims and tolerances was issued as in below:
Used for 57-76 Sportster gear shaft roller bearingsDiameterSizeLength
9421.1876“ - 1974”Standard.800“ - .796”
9422.1878“ - 1876”+ .0002“.800” - .796“
9423.1880” - .1878“+ .0004”.800“ - .796
9424.1882” - .1880“+ .0006”.800“ - .796”
9425.1884“ - .1882”+ .0008“.800” - .796“
9426.1886” - .1884“+ .0010”.800“ - .796”
Used for 54-85 Sportster and K Model front crankpin roller bearingsDiameterSize
9150A.1875“ - .1874”Standard.480“
9152A.1877” - .1976“+ .0002”.480“
9154A.1879” - .1878“+ .0004”.480“
9156A.1881” - .1880“+ .0006”.480“
9158A.1883” - .1882“+ .0008”.480“
9160A.1885” - .1884“+ .0010”.480“
9161.1873” - .1872“- .0002”.480“

Primary / Chain Cover

All part numbers were gathered from period specific Sportster parts catalogs from 1957-1985 including supplement and updated catalogs.

Year
Model
Part
Number
Casting
Number
GasketStarter
Shaft
Bearing
Oil Filler
Plug/Cap
Clutch Adj
Hole Plug
1952-1953 K Models34951-5234950-5234955-52N/A24742-52N/A
1954-1956 K Models34951-5434950-52A34955-52AN/A24742-52N/A
1957-1966 XL/XLH34951-5734950-5734955-52AN/A34742-52AN/A
Notes:Sand cast aluminum. Natural finish
1958-1969 XLC/XLCH34949-58none 34952-52N/A60569-29N/A
Notes:Black, stamped steel
1964-1969 XLCH34949-64none34952-52N/A60570-64N/A
Notes:Chrome, stamped steel
1967-1970 XLH34947-6734950-6734955-67906334742-52AN/A
Notes:Sand cast aluminum
1970 XLCH34948-7034950-6734955-67N/A34742-52AN/A
Notes:Sand cast aluminum, not drilled for starter shaft bearing.
Dowel hole near bearing area not drilled
1971 XLCH34948-71 34955-67906334742-7137880-71
Notes:Die Cast Aluminum. Name transfer “900” in center. Replaced by 34949-71 (1972).
Extra removable plug cap added to cover for wet clutch adjustment.
1971-1972 XLH/XLCH
1974-1976 XLH/XLCH 62)
34949-71 34955-67906334742-7137880-71
Notes:Polished. Name transfer “900” in center (1971). Name transfer “1000” in center (1972-up)
Extra removable cap added to cover for wet clutch adjustment.
1973 XLH/XLCH34949-73 63) 34955-67906334742-7137880-71
Notes:Black. Name transfer “1000” in center
1975-1976 XLH/XLCH34949-75 64) 34955-67906334742-7137880-71
Notes:Polished. Name transfer “900” in center
1977 XLH/XLCH34949-75 65) 34955-75906334742-7734742-77
Notes:Polished. Name transfer “Sportster” in center.
Replaced by (34949-75A) in 1978 66)
1978-1979 XLH/XLCH34949-75A 67) 68) 69) 34955-75906334742-77A34742-77A
Notes:Polished. Replaced by polished cover from kit (34949-75A). Also replacement for 1977 XLH/XLCH
Name transfer “Sportster” in center. Later replacement cover 25430-81.
34956-78 70) 34955-75906334742-77A34742-77A
Notes:Polished. Replaced by polished cover from kit (34949-75A). Also replacement for 1977 XLH/XLCH
Name transfer “Sportster” in center. Later replacement cover 25430-81.
1979 XLS34941-79 34955-75906334742-77A34742-77A
Notes:Gray. Name transfer “1000” in center. Replacement cover 25430-81
1980 XLH34946-78 34955-75906334742-77A34742-77A
Notes:Polished. Part number for cover assembly. Name transfer “Sportster” in center
25423-80 34955-75906334742-77A34742-77A
Notes:Polished, part number for cover assembly. Name transfer “Sportster” in center
1980 XLS25422-80 34966-80906334742-77A34742-77A
Notes:Black, cover and gasket. Part# for cover assembly. Name transfer “1000” in center
25424-80 34966-80906334742-77A34742-77A
Notes:Black, cover and gasket. Part# for cover only. Name transfer “1000” in center
1981-E1984 XLH
1983-E1984 XLS
25430-8134950-75B34955-75N/A34742-77A34742-77A
Notes:Polished. Starter doesn't require bearing in primary cover.
Bearing boss still present with hole milled for 1979-1980 bearing.
1981-1982 XLS25424-81 34966-80N/A34742-77A34742-77A
Notes:Black, cover and gasket. Ribbed across center.
1983-E1984 XLX25433-83 34955-75N/A34742-77A34742-77A
Notes:Aluminum finish.
L1984-1985 XLH/XLS25430-84 34955-75N/A34742-77B34742-77B
Notes:Polished
L1984-1985 XLX25433-84 34955-75N/A34742-77B34742-77B
Notes:Aluminum finish
1) , 2) , 3) , 4) , 13) , 15)
photos courtesy of Ebay seller, Sum-body's Harley Parts, Link to Ebay Store
5) , 20) , 24)
photo courtesy of Ebay seller, jrsvintageharley1990. Link to Ebay Store
6) , 7)
photo courtesy of Fox Cycle Works, Link to Ebay Store
8) , 34) , 35) , 36)
photos courtesy of Ebay seller, Robison Motorcycles Link to Ebay Store
9)
photo courtesy of Ebay seller, Robison Motorcycles Link to Ebay Store
10)
photo by Ebay seller, johngoober, Link to Ebay Store
11)
photo courtesy of Ebay seller, market406. Link to Items for Sale page
12)
photo courtesy of NitroFrankie Go-Fast HD, Ebay Items for Sale Page
14)
photos courtesy of Ebay seller, 57harleyrider. Link to Ebay Store
16)
photos courtesy of Ebay seller, animalhouse2010, Link to Ebay store:
17) , 43)
TSB M-778 dated May 13, 1980
18)
photo courtesy of Ebay seller, inlinefabrication. Link to Ebay Store
19)
photo courtesy of c3cycle.com, Link to site: https://www.c3cycle.com/
31) , 33)
Dims from Robison Motorcycles
37)
photo courtesy of C & M Sales, Link to Ebay Store
38)
photo courtesy of Ebay seller, cyclewarehouse. Link to Items for Sale
39) , 40)
TSB# 537 dated March 22, 1966
42)
TSB# 652 dated July 30, 1973
44)
TSB m-870 dated April 15, 1983
45)
correction noted in Parts and Accessories Bulletin #213 dated January 10, 1984
46)
TSB M-872 dated August 18, 1983
47)
TSB M-781 dated May 23,1980
48) , 57)
1957 parts catalog
49) , 58)
1958 parts catalog supplement
50)
1980 parts catalog
51) , 52) , 54) , 55) , 56)
TSB M-829 dated 5-19-1981
53)
HD 1979-1982 Parts Catalog pg 11
59)
HD Service Bulletin #M-829 dated May 19, 1981
60)
HD Service Bulletin #M-829A dated June 12, 1981
61)
HD Service Bulletin #M-840 dated October 2, 1981
62) , 63)
1974 Sportster Parts Catalog Supplement
64)
1975 Sportster Parts Catalog Supplement
65)
1977 Sportster Parts Catalog Supplement
66) , 67)
1978 Sportster Parts Catalog Supplement
68)
1978 Sportster -78A Parts Catalog
69) , 70)
1980 Sportster Parts Catalog
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