IH: Suspension

Swingarm (rear fork) Info

A number of 1972 Sportsters were produced from November 1, 1971 to March 29, 1972 without the (3 position) stake operation performed on the rear left side fork bearing lock nut (47514-52). Bearing pre-load (which should be kept at 1-2 pounds) is controlled by the left and right (47515-52) bearing lock nuts. The affected VINs were (3A or 4A) 18748H2 to 33040H2. This safety defect prompted a recall of the affected bikes with the dealer being required to remove the rear fork for inspection and stake any of them that were done previously at a rate of $7 reimbursed labor and handling. 1)

  • There are 4 variants of the long swingarm
    1. 67-72 xlh 70-72 xlch
    2. 73 & 74 all- starting in 73 the 'new' brake anchor came out. the one that needs to be loosened to adj chain. this arm got addl machine work at anchor 'top hat' seat
    3. 75 & 76 all
    4. 77 & 78 all but xlcr
Short and Long Swingarm 2)

Swingarm Swaps

  • Pre-1979, only the 1977 XLCR had the box arm with Disc. 3)
  • 1979 - 1981 had the box arm with disc and it will fit pre-79 frames. 4)
  • A 79-81 swing arm will bolt on a 72 frame. Things to consider when changing swingarms are master cylinder placement, operation and the fact that the 79-81 swing arm shock mounting will change the angle of your shocks. 5)
  • Consider if you even want a disc on the rear. It won't work any better than the drum, which is already powerful enough to lock up the wheel. Put your effort into improving the front brake if you want to stop better. 6) You would do better by adapting a later 39 MM Evo fork for brakes and handling. 7)

Swingarm

Removing the Swingarm

  • Follow the procedure in your FSM to remove the swingarm. However, if you can do it without removing the staked nut on the left side is best. It serves to center the swingarm in the frame and you can bung up the threads on that nut really easily. 8)

Assembling the Swingarm

  • For the swing arm its pretty easy when you know how it works. The pivot bolt when tightened presses the inner bearing and race,bearing spacer, and dust shield onto both sides of the frame and the actual adjustment is done by tightening bearing locknut on the right side till you have the desired preload once the preload is set then comes the lock-ring so the right bearing locknut cant turn. 9)
  • When you install the locknut do not stake it as advised in the FSM. A little [not a lot] of blue locktite is all that it needs, and whoever needs to remove it one day will be thankful. 10)
  • Factory recommendation from bulletin in 1972: 11)
  • Reinstall rear fork (be sure the left side nut registers in the crankcase slot). Weigh with spring scale before tightening the right side bearing race nut.
  • Tighten nut until you get 1-2 pounds of bearing preload. Install the bearing nut lock and screw.

Guide to Swingarm Bearing Replacement

Article and Pics by ericfreeman of the XLFORUM 12)
Click on a pic to enlarge:

Here are all the parts laid out as they will fit
into the swingarm 13)
The bearing outer races are already installed
in the swingarm 14)
Inspect the swingarm inner surfaces to ensure they
are clean. You can see the bearing outer race
already installed in the other side. 15)
Use some 800 wet/dry sandpaper to smooth
the surface 16)
Press the outer races into place using an
appropriate tool.17)
Grease the tapered roller bearing. I used a very
sticky marine grease that won't wash out. It's not
for bearings that rotate at high speed like wheel
bearings but will be fine for the swingarm that just
oscillates through a small arc. 18)
Install the bearing in the outer race19)Pack the area around the bearing with more grease
and fit the spacer on the bearing, with the smaller
diameter section facing up so it will fit into the hole
in the dust cover.20)
Install the dust seal, ensuring it fits flush with the
swingarm boss. The flat side of the spacer should
protrude a little through the dust seal hole. This
spacer will seat against the frame when the bearing
preload is set.21)
Here's the outer view of the leftside assembly, with
the pivot bolt nut and bearing locknut in place. I'll wait
to lock the bearing locknut into place until I trial-fit
the swingarm to ensure I can properly adjust the left
bearing preload.22)
Repeat the procedure on the other side. Here's
what it looks like with both bearings installed.23)
This is the entire setup assembled to keep all the
parts together prior to fitting the swingarm
in the frame.24)

Installing the Swingarm

Swingarm Parts List

Year ModelSwingarm Part #
1952-1956 All K Models
1957 Sportster
47504-52
replaced by 47504-52A 25) 26)
replaced by 47504-52B 27)
All new versions are retro-fit
1967-1969 XLCH47504-56B 28)
1967-1974 XLH
1970-1974 XLCH
47504-67A 29)
1975-1976 XLH, XLCH47504-75 30)
1977-1978 XL, XLCH47504-76 31)
1979 XL/XLCH/XLS47532-79 (with bearings) 32)
1979 XL/XLCH/XLS47549-79 (without bearings) 33)
1979-1981 XL/XLCH/XLS47532-79A (with bearings) 34)
1979-1981 XLCH
1979-1981 XL/XLS
47473-80 (without bearings) 35)
1982 XL/XLS47532-81 (with bearings) 36) Square Tube 37)
1983-1985 XL/XLS/XLX47532-83 (with bearings) 38) Square Tube 39)
Inner Bearing ShieldPart #Inner Bearing SpacersPart #Outer Bearing Spacer (R)Part#
52-56 K Models
57-81 XL/XLH/XLCH/XLS
(2) 47519-5252-56 K Models
57-81 XL/XLH/XLCH/XLS
(2) 47518-5252-56 K Models
57-E74 XL/XLH/XLCH
47517-52
L74-81 XLH/XLCH/XLS47517-74
Swingarm BearingsPart #Swingarm BearingsPart #
52-56 K Models
57-E74 XL/XLH/XLCH
(2) 47521-52
Timken: Race 17520, Bearing 17580 40)
82-85 XL/XLS/XLX(left) (1) 47083-81
54-E74 KH/XL/XLH/XLCHBearing Kit 47550-74 82-85 XL/XLS/XLX(Right) (2) 47082-81
Timken: Race LM11710, Bearing LM11749 41)
L74-81 XLH/XLCH/XLS(2) 47521-74
Timken: Race 11520, Bearing 11590 42)
  • Bearing Kit (47550-74) (replaced the single bearing part # 47521-52) contains 2 bearings which are 0.100“ narrower than the original bearing dims used in Sportsters up to February of 1974. The kit also contains a new pivot bolt nut (47512-74), bearing locknuts (L - 47514-74, R - 47515-74) and an outer spacer (47521-74) - clearanced for the new bearings. 43)
  • Caution: Parts must not be intermixed on a complete rear fork pivot shaft and bearing assembly. Correct bearing clearance and specified fork bearing preload cannot be obtained with intermixed parts. Correct bearing preload is essential for satisfactory operation and proper motorcycle handling. 44)
Bearing Locknut Lock-plate (R)Part #
52-56 K Models
57-81 XL/XLH/XLCH/XLS
47525-52
(#10)Bearing Retention:
Lock-Plate Screw / Washer / Lockwasher (R)
Part #
52-56 K Models
57 Sportster
1187
52-56 K Models
57-63 XL/XLH/XLCH
(#10 x 3/8” self tapping) 2657
52-56 K Models
57-59 Sportsters
(#10×13/32“) External tooth shake-proof lockwasher 7220
53-63 K Models
57-63 XL/XLH/XLCH
5/8” Lockwasher 7072
L72-81 XLH/XLCH/XLS(10-24 x 1/2“) Pozidriv fil head (R) 1198
L72-81 XLH/XLCH/XLS(#10) Lockwasher (R) 7069
54-81 KH/XL/XLH/XLCH/XLS(5/8”) Bearing Lockwasher 7022
Swingarm Pivot Bolt / NutPart #
54-81 KH/XL/XLH/XLCH/XLS47511-52
82-85 XL/XLS/XLX41568-81A
Pivot Bolt NutPart #
52-56 K Models
57-E74 XL/XLH/XLCH
47512-52
L74-81 XLH/XLCH/XLS47512-74
Bearing LocknutPart #
52-56 K Models &
57-E74 XL/XLH/XLCH
47514-52 (Left) 45)
52-56 K Models &
57-E74 Sportster
47515-52 (Right) 46)
L74-81 XLH/XLCH/XLS47514-74 (Left)
L74-81 XLH/XLCH/XLS47515-74 (Right)
Axle AdjusterPart #
54-78 KH/XL/XLH/XLCHAxle Adjuster (2) 39985-52
79-85 XL/XLCH/XLS/XLXAxle Adjuster (2) 41570-77
Axle Adjuster Nuts / WashersPart #
54-78 KH/XL/XLH/XLCHInner Axle Adjuster Nut (2) 7753 (5/16“-24 NF x 17/64” x 1/2“ hex)
54-78 KH/XL/XLH/XLCHOuter Axle Adjuster Nut (2) 7744 (5/16”-24 NF x 3/16“ x 1/2” hex)
79-85 XL/XLCH/XLSWasher, (2) 6324W (5/16“ x 11/16” x 3/32“)
79-85 XL/XLCH/XLSLocknut,(2) 7725 (5/16”x24 x 11/32“ x 1/2” hex)
Fork End CoversPart #
79 XL/XLCH/XLS(2) 47554-78
79-85 XL/XLCH/XLS/XLX(2) 47554-73
Bearing Dust ShieldPart #
82-85 XL/XLS/XLX(2) - (right) 41579-81
Pivot Bolt SpacerPart #
82-85 XL/XLS/XLX(left) 5716
Plastic Bearing PlugPart #
83-85 XLX(Left) 10040
Passenger Footpeg BracketPart #
83-85 XL/XLS (2) 50615-83
83-85 XL/XLS3/8“ Lockwasher for Footpeg Bracket (2) 7045
83-85 XL/XLS3/8”x16 2“ Knurled 9/16” Socket Head Screw (2) 855
for Passenger Footpeg Bracket

Swingarm Pics

Click on a pic to enlarge:

1980 Swingarm bolt assembly 47)


1)
HD Service Bulletin #636 dated April 27, 1972 pg OC-403
11)
HD Service Bulletin #636 (included instruction sheet) dated April 2, 1972
13) , 14) , 15) , 16) , 17) , 18) , 19) , 20) , 21) , 22) , 23) , 24)
Pics by ericfreeman of the XLFORUM http://xlforum.net/forums/showthread.php?t=709634
25)
Spare Parts Catalog for all Sportster and K Models pg 38 by OSKRG/ www.harleyKmodel.com
26)
HD 1952-1959 Spare Parts Catalog for Sportsters and K Models pg 45
27)
1963 HD Parts Catalog for Sportsters and KH Models 1953-1963 pg 50
28) , 29) , 30) , 31)
1952-1978 HD Parts Catalog pg 111
32) , 33)
1979 HD Sportster Parts Catalog pg 53
34) , 35)
1979-1985 HD Sportster Parts Catalog pg 87
36) , 38)
1979-1985 HD Sportster Parts Catalog pg 89
43) , 44)
HD Service Bulletin #688 dated May 12, 1974
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