Table of Contents
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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
- 67-72 xlh 70-72 xlch
- 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
- 75 & 76 all
- 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 Model | Swingarm 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 XLCH | 47504-56B 28) | ||
1967-1974 XLH 1970-1974 XLCH | 47504-67A 29) | ||
1975-1976 XLH, XLCH | 47504-75 30) | ||
1977-1978 XL, XLCH | 47504-76 31) | ||
1979 XL/XLCH/XLS | 47532-79 (with bearings) 32) | ||
1979 XL/XLCH/XLS | 47549-79 (without bearings) 33) | ||
1979-1981 XL/XLCH/XLS | 47532-79A (with bearings) 34) | ||
1979-1981 XLCH 1979-1981 XL/XLS | 47473-80 (without bearings) 35) | ||
1982 XL/XLS | 47532-81 (with bearings) 36) Square Tube 37) | ||
1983-1985 XL/XLS/XLX | 47532-83 (with bearings) 38) Square Tube 39) |
Swingarm Pivot Bolts, Bearings and Related Parts List
Inner Bearing Shield | Part # | Inner Bearing Spacers | Part # | Outer Bearing Spacer (R) | Part# |
52-56 K Models 57-81 XL/XLH/XLCH/XLS | (2) 47519-52 | 52-56 K Models 57-81 XL/XLH/XLCH/XLS | (2) 47518-52 | 52-56 K Models 57-E74 XL/XLH/XLCH | 47517-52 |
L74-81 XLH/XLCH/XLS | 47517-74 |
Swingarm Bearings | Part # | Swingarm Bearings | Part # |
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/XLCH | Bearing 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)
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 / Nut | Part # |
54-81 KH/XL/XLH/XLCH/XLS | 47511-52 |
82-85 XL/XLS/XLX | 41568-81A |
Pivot Bolt Nut | Part # |
52-56 K Models 57-E74 XL/XLH/XLCH | 47512-52 |
L74-81 XLH/XLCH/XLS | 47512-74 |
Bearing Locknut | Part # | |
52-56 K Models & 57-E74 XL/XLH/XLCH | 47514-52 (Left) | 44) |
52-56 K Models & 57-E74 Sportster | 47515-52 (Right) | 45) |
L74-81 XLH/XLCH/XLS | 47514-74 (Left) | |
L74-81 XLH/XLCH/XLS | 47515-74 (Right) |
Axle Adjuster | Part # |
54-78 KH/XL/XLH/XLCH | Axle Adjuster (2) 39985-52 |
79-85 XL/XLCH/XLS/XLX | Axle Adjuster (2) 41570-77 |
Axle Adjuster Nuts / Washers | Part # |
54-78 KH/XL/XLH/XLCH | Inner Axle Adjuster Nut (2) 7753 (5/16“-24 NF x 17/64” x 1/2“ hex) |
54-78 KH/XL/XLH/XLCH | Outer Axle Adjuster Nut (2) 7744 (5/16”-24 NF x 3/16“ x 1/2” hex) |
79-85 XL/XLCH/XLS | Washer, (2) 6324W (5/16“ x 11/16” x 3/32“) |
79-85 XL/XLCH/XLS | Locknut,(2) 7725 (5/16”x24 x 11/32“ x 1/2” hex) |
Fork End Covers | Part # |
79 XL/XLCH/XLS | (2) 47554-78 |
79-85 XL/XLCH/XLS/XLX | (2) 47554-73 |
Bearing Dust Shield | Part # |
82-85 XL/XLS/XLX | (2) - (right) 41579-81 |
Pivot Bolt Spacer | Part # |
82-85 XL/XLS/XLX | (left) 5716 |
Plastic Bearing Plug | Part # |
83-85 XLX | (Left) 10040 |
Passenger Footpeg Bracket | Part # |
83-85 XL/XLS | (2) 50615-83 |
83-85 XL/XLS | 3/8“ Lockwasher for Footpeg Bracket (2) 7045 |
83-85 XL/XLS | 3/8”x16 2“ Knurled 9/16” Socket Head Screw (2) 855 for Passenger Footpeg Bracket |
Swingarm Pics
1)
HD Service Bulletin #636 dated April 27, 1972 pg OC-403
2)
photo by Dr Dick of the XLFORUM® http://xlforum.net/vbportal/forums/showthread.php?t=1062720&page=23
11)
HD Service Bulletin #636 (included instruction sheet) dated April 2, 1972
13)
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Pics by ericfreeman of the XLFORUM http://xlforum.net/vbportal/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
43)
HD Service Bulletin #688 dated May 12, 1974
46)
photo by OutlawTexan67 http://xlforum.net/vbportal/forums/showthread.php?t=185355