EVO: Suspension

Sub-Documents

Front Fork Info

Illustration created by IXL2Relax at the XLForum The front forks on most Sportster models consists of two tubes - A slider tube that is mounted in the triple-trees and a lower leg tube into which the slider tube compresses. Each slider/leg assembly has an internal compression spring and damper tube. The spring supports the weight of the rider & bike, collapsing or expanding to cushion the ride over bumps and cavities in the road surface. The damper tube is submerged in oil and uses the passage of oil between internal chambers to help control the speed with which the slider/leg assembly compresses together & expands apart as it cushions the ride. Because the damper tube is attached to the lower leg, the length of the damper tube determines the amount of 'travel' the slider tube has within the lower leg.

In addition to the internal physical spring, there is an 'air spring' effect caused by the amount of air above the oil level in the fork assembly.

Functionally, there must be enough fork oil to fully submerge (engulf) the damper tube during its entire operational movement. The MoCo specified oil amount still leaves an air pocket above the level of the oil in the fork.

The air captured between the top of the oil level and the fork caps (which are sealed) creates an 'air spring' by which the compression of the air during fork compression helps the physical spring prevent total collapse of the fork, while also assisting the spring in expanding the fork after a compression event. The size of the air pocket, measured by determining the exact distance the top of the oil is from the top of the slider tube, can be varied (by adding or reducing oil) to produce a stronger or weaker 'air spring' effect (but the adjusted oil level must still allow the damper tube to be fully submerged during its entire operational movement).

Here's an example of the parts for that design (1994 Sportster XLH): 1)

Image by seraphan6 XLForum Threadid=1085901 Here's a comparison between a couple damper tube sets. Notice they are of different lengths and that the holes at the bottom are different sizes. The actual length & size of holes varies by the model in which it is intended to be used.

The length of the tube partly detemines the overall slide movement range. The size of the holes at the bottom of the tube determines the rate of exchange of the oil between internal chambers when the fork is compressed. This helps control how quickly the forks compress.

The set of damper tubes on the left includes the 'top out' springs which help cushion the end of travel when the forks expand. All models use the same top out springs (as stock).

Racetech has a fairly detailed explanation of Damper Rod Forks, along with their promotion of cartridge emulators, at this site: http://racetech.com/html_files/dampingrodforks.html




1986-2003 Forks (Except 1200S)

Abbreviations:

  • Std = 883 Standard Model & 1200 Standard Model
  • Dlx = 883 Deluxe Model
  • Hug = 883 Hugger Model
  • Ctm = 883 Custom Model & 1200 Custom Model

Upper Slider Tube, Damper Tube & Spring (same on both sides)

1986 Late Std & Dlx
-198735mm TubesStd & Dlx & HugLength
Slider Tube45407-8623.25“
Damper Tube45913-84
Spring-#Coils45907-8320.25”
1988-199139mm Tubes Std & Dlx & HugLength
Slider Tube45381-8723.375“
Damper Tube45925-8810.875”
Spring-#Coils45376-8720.25“
1992Models »Std&DlxLengthHuggerLength
Slider Tube45381-8723.375”45395-9224.25“
Damper Tube45925-8810.875”45938-927.5“
Spring-#Coils45376-8720.25”45372-9221.5“_47coils
1993
Slider Tube45381-8723.375”45395-9224.25“
Mid-yearSlider Tube45395-9224.25”
Damper Tube45925-8810.875“45938-927.5”
Spring-#Coils45376-8720.25“45372-9221.5”_47coils
1994-1995
Slider Tube45395-9224.25“45395-9224.25”
Damper Tube45925-949.50“45938-927.5”
Spring-#Coils45376-9421.5“_53coils45372-9221.5”_47coils
1996Models »StdLengthHug&CtmLength
Slider Tube45395-9224.25“45395-9224.25”
Damper Tube45925-949.50“ 45938-927.5”
Spring-#Coils45376-9421.5“_53coils45372-9221.5”_47coils
1997Models »Std&CtmLengthHuggerLength
Slider Tube45395-9723.375“ 45395-9224.25”
Damper Tube45925-979.0“45938-927.5”
Spring-#Coils45376-97 45372-9221.5“_47coils
1998Models »StdLengthHug&CtmLength
Slider Tube45395-9723.375” 45395-9224.25“
Damper Tube45925-979.0”45938-927.5“
Spring-#Coils45376-97 45372-9221.5”_47coils
1999-2003Models »Std&CtmLengthHuggerLength
Slider Tube45395-9723.375“45395-9224.25”
Damper Tube45925-979.0“45938-927.5”
Spring-#Coils45376-97 45372-9221.5“_47coils
2002-2003Models »883RLength
Slider Tube45395-9723.375”
Damper Tube45925-979.0“
Spring-#Coils45376-97

Slider Lower Legs (Except 1200S)

Model(s)Lower Sliders
Left Leg
Lower Sliders
Right Leg
1984-1987 2)3)All45912-8445906-84
1988-1999 4) 5)
6) 7) 8) 9) 10)
All45921-8745923-87
2000-2003 11) 12)
13)14)
All
(Except 883R)
45921-0045923-00
2002-2003 15)16)XL883R45921-0045922-00


Spring Rates:
45372-92 - 21.5” - 47coils - Rate reported as 40#/in 17)


1996-2003 Forks For 1200 Sport Model

XL1200S Sport Model - Fork Parts

See also Setting up the 1200S Suspension

Fork Parts Length
1996-2003Upper Slider Tube45366-96
Cartridge Damper Tube46024-96
Cartridge Spring-#Coils45367-96
Same parts used on both left & right sides

Slider Lower Legs

Model(s)Lower Sliders
Left Leg
Lower Sliders
Right Leg
1996-1999 18) 19) 20) 21) XL1200S46023-9646022-96
2000-2003 22) 23)24)25)XL1200S46023-0046022-00


Draining 1200S Forks

  • 1200S sliders don't have drain plugs. So, here is one way of doing so. 26)
  • Basically, once you have the forks out of the bike, remove the large top nut (loosen it slightly while you have the forks clamped in the lower triple tree, (as shown here Part 4 Dismantle the Forks ) while holding the slider. There is no spring pressure on this nut, so it's easy. 27)
  • The slider will drop away, but don't let it drop more than a couple of inches or you'll have oil pouring out and not know how much has come out. 28)
  • Carefully tip the fork upside-down and pour the oil into a clear measuring container (a wide funnel will help you to not lose any). 29)
  • Bring the fork upright and pull the slider to the very top again, pump the fork a few times to empty the damper tube, then turn it upside-down again and pour more oil into your measuring container. Repeat this a couple more times to get as much of the old oil out as possible. 30)
  • Check how much oil came out of the fork, make a note of it, then pour the old oil into a waste container. 31)
  • Measure the same quantity of fresh oil into the measuring container, then, with the slider still close to the top of its stroke, carefully pour the oil into it. You're pouring the oil between the coils of the spring, so you need to go slowly and keep the fork vertical to avoid losing any. If you can get your hands on a funnel and fit a narrow flexible hose to the end of it, it may make things easier. 32)
  • When all the fresh oil is in, thread the slider onto the top nut again; clamp the fork into the bottom triple tree only to hold it steady while you fully tighten the top nut; then push the fork all the way to the top again and clamp it in place. 33)
  • Repeat on the other fork. 34)



2004-later Forks

  • Be careful, with the Low bikes, taking out the shock caps. There is about 2 1/2 “ of spring preload so the cap wants to come out in a hurry. I am about 200 lbs and fairly strong and it was about all I could do to reinstall the caps with a 1 3/8 socket on a 6” extension on a ratchet. 35)

Damper Tube Forks

(Same parts used on both left & right sides)


Models
Upper
Slider Tube

Damper Tube

Spring

Notes
2004-2008 04-08 883/C 1200C/R
05-08 883R
07 XL50 Annv
45395-0445925-0445376-04DT=9.0“ - 45925-04
2005-2006 883L 46218-0545938-9246267-05DT=7.5” - 45938-92
2006-2011 1200L 46218-0545938-9246267-05DT=7.5“ - 45938-92
2007-2010 883L 46218-0547313-0747299-07DT=7.0” - 47313-07 w/ 2-holes 8.92mm
2007-2012 1200N 46218-0547313-0747299-07DT=7.0“ - 47313-07 w/ 2-holes 8.92mm
2009 883 1200R 45395-0945925-0945376-09DT=7.5” - 45925-09
2009-2010 883C/R 1200C 45395-0945925-0945376-09DT=7.5“ - 45925-09
2009-2013 883N 46218-0547313-0747299-07DT=7.0” - 47313-07 w/ 2-holes 8.92mm
2010-2015 1200X (48) 45395-091062710417
2011-2015 883R 45395-0945925-0945376-09DT=7.5“ - 45925-09
2011-2015 883L 46218-0545938-9246267-05DT=7.5” - 45938-92
2011-2015 1200C/CP 45395-0945458-0946245-09DT=7.5“ - 45458-0936)
2013 1200C - Annv 45395-0945458-0946245-09DT=7.5” - 45458-0937)
2013-2015 1200 CA/CB 45395-0945458-0946245-09DT=7.5“ - 45458-0938)
2013-2015 1200V (72) 45395-0945925-0945500142DT=7.5” - 45925-09
2014-2015 883N 46218-0547313-0745500139DT=7.0“ - 47313-07 w/ 2-holes 8.92mm
2014-2018 1200T 45395-0945458-0945500244DT=7.5” - 45458-0939)

(Measurements for this section contributed by XLForum members)

Mixed-Tech Forks

These forks use a combination of Left-side Cartridge & Right-side Damper Tube


Models
Upper
Lt Slider

Lt Cartrdg

LtSpring
Upper
Rt Slider

Rt Damper

Rt Spring
2016 1200CA 45500280 45500282 45500274 45500281 45500278 45500275
2016 1200CP 45500280 45500282 45500274 45500281 45500278 45500275
2016-2017 1200CB 45500280 45500282 45500274 45500281 45500278 45500275
2016-2018 883L 45500280 45500282 45500274 45500281 45500278 45500275
2016-2018 883N 45500280 45500304 45500300 45500281 45500302 45500301
2016-2018 1200C 45500280 45500282 45500274 45500281 45500278 45500275
2016 1200X (48) 45500280 45500304 45500300 45500281 45500302 45500301
2016 1200V (72) 45500280 45500283 45500276 45500281 45500279 45500277
2017-2018 1200X (48) 45500295 45500296 45500293 45500295 45500298 45500294


Here's a thread by 'Tomcatt' of the XLForum regarding changing to aftermarket springs & changing the oil viscosity/level in these mixed-tech forks:
http://xlforum.net/forums/showthread.php?t=2073068


Inverted Forks

Inverted Forks use an upper slide tube that is the larger, outer tube while the lower, inner slider tube is used to attach the wheel. This is upside-down from the traditional damper tube design.

Models Upper Left Fork Right Fork Notes
Models Outer Tube Cart/RodSpring RodSpring Notes
2008-2009 XR 1200 46884-0846878-0846882-0846359-0646882-08Lt uses Cart/Sprg - Rt uses Rod/Sprg
2010 XR 1200 &
XR 1200X
10628 46681-101041846681-101041846681-10 is Compl. Rod Assy (each side)
2011-2013 XLR 1200X 10628 46681-101041846681-101041846681-10 is Compl. Rod Assy (each side)
2016-2018 XL1200CX Roadster 4550035845500371455003694550036145500369Lt uses Cart/Sprg - Rt uses Rod/Sprg

Slider Lower Legs


Model(s)
Lower Sliders
Left Leg
Lower Sliders
Right Leg
Rt Brk
Mount

Notes
2004 40)883/883C/1200C45921-0045923-00 ?
2004-200741) 42)43)44)1200R45921-0045922-00
2005-200645)46)883/883L
883C/1200C
45921-0045923-00 ?
2005-200747)48)49)883R46450-0546449-05 ?
2007 50)All except 883R
1200R/1200N
45921-0045923-00 ?
200751)1200N48726-0748716-07 ?
2008 52)All except 883R
1200R/1200N
46075-0446076-04 ?
2008-2013 53)54)55)56)57)58)883R46450-0846449-08 ?
2008-2009 59)60)1200R46075-0445922-08 ?
2008-2012 61)62)63)64)65)1200N48726-0848716-08 ?
2008-201066)67)XR120046880-0846879-08 YES Inverted Forks
2009 68)883/883C/883L
1200C/1200L
46075-0446076-04 ?
2009-2014 69)70)71)72)73) 74)883N48726-0848716-08 ?
2010 75)883C/883L
1200C/1200L
46075-0446076-04 ?
2010-2015 76)77)78)79) 80) 81)XL1200X48850-1048849-10 ?
2010-2013 82) 83)84)85) 86)XR1200X48786-1048785-10 YES Inverted Forks
2011 87)1200L46075-0446076-04 ?
2011-2018 88)89) 90) 91) 92)93)883L49401-1149403-11 No
2012 94)1200C/CP49411-1149412-11 ?
2013 95)1200V46075-0446076-04 ?
2013 96)1200C/C-Anniv/CP/CA/CB49411-1149412-11 ?
2014-2016 97) 98) 99)1200V4550005645500075 ?
2014-2015 100) 101)883R4550005545500076 ?
2014-2016 102) 103) 104)1200C/CP/CA/CB49411-1149412-11 ?
2015-2018 105) 106)883N4550005445500057 No
2015-2018 107) 108)1200T49401-1149403-11 No
2016-2018 109)XL1200X4550028745500290 No
2016-2018 XL1200CX Roadster4550035945500360 YES Inverted Forks
2017 1200C/CB49411-1149412-11 No
2018 1200C & Anniv4550051145500510 No

Reference Additional Information on the 2004+ models in these XLForum Threads:
http://xlforum.net/forums/showpost.php?p=3265511
http://xlforum.net/forums/showthread.php?t=1827354
http://xlforum.net/forums/showthread.php?t=1085901
http://xlforum.net/forums/showthread.php?t=1971682


Fork Service Kits

The Fork Service Kit is a collection of the parts recommended to be replaced for refresh maintenance. It includes all the parts that function between the Upper Slide Tube and the Lower Slide Tube plus new damper/cartridge mounting screws & Fork Cap Seals (O-ring).

For the models that use the same Fork Service Kit, one might expect the upper & lower slide tubes to be functionally compatible across all years (that's an assumption - there might be something that IS incompatible - but unknown).

1988-2018 2016+ 2016+ Inv Forks Notes:
All Except » Model 48 Roadster
Full Service Kit » 49378-09 45500307 49380-09
Includes the following parts in the kits:
Slide Bushing 45465-87 46080-01 46348-06 On Inner Slide Tube
Dust Seal 45401-87 46512-01A J8130.3A8 Into Outer Slide Tube
Stopper Ring 45905-87 46513-01 45842-77A Wire Retaining Clip
Oil Seal 45378-87 46514-01A 12085 Into Outer Slide Tube
Seal Spacer 45377-87 46515-01 46346-06 Into Outer Slide Tube
Guide Bushing 45461-87 46516-01 46343-06 Into Outer Slide Tube
Damper Rod Seal Ring 45462-87 22000031 ——– At Top of Damper Tube
Damper Rod Screw 45405-75A ——– 45405-75A Thru Axle Hole - Incl Washer
O-ring for Cap 45984-87 46508-01 46329-06 Fork Cap Seal
–Separately– No Yes No
Washer for DR Tube N/A 46615-06 N/A
Damper Rod Screw Rt N/A 45500118 N/A
Damper Rod Screw Lt N/A 45500236 N/A

Fork Oil Drain Screws

45790-80 - Stock JIS-head Drain Screw with Washer (Requires 1 for each fork)

  • (Starting in 2008, some models do not have fork oil drain screws)
  • (Use a JIS screwdriver for JIS screws. JIS screws look like Philips screws with a dot in the center of the head, but the JIS version is a wider blade with different spline angles. Using a Philips screwdriver on a JIS screw will often round out the screw head. However, using a JIS screwdriver on a Philips-head screw may work just fine, since the driver splines fit snugly on the upper, heavier part of the screw head.)

45815-03 - Chrome Fork Slider Drain Screw Kit110)
Screw size is M4 (0.7mm) × 6mm - Includes a pair of chrome allen head drain screws and washers - Uses 2.5mm allen key



1)
Photo by IXL2Relax at the XLForum
2)
1979-1985 HD Sportster Parts Catalog pg 83,85
3) , 4)
1986-1990 HD Sportster Parts Catalog pg 65
5)
1991-1992 HD Sportster Parts Catalog pg 65
6)
1993-1994 HD Sportster Parts Catalog pg 61
7)
1995-1996 HD Sportster Parts Catalog pg 61
8) , 19)
1997 HD Sportster Parts Catalog pg 61
9)
1998 HD Sportster Parts Catalog pg 63
10)
1999 HD Sportster Parts Catalog pg 67
11)
2000 HD Sportster Parts Catalog pg 67
12)
2001 HD Sportster Parts Catalog pg 69
13) , 15)
2002 HD Sportster Parts Catalog pg 69
14) , 16)
2003 HD Sportster Parts Catalog pg 69
17)
by sebasbecu at xlforum.net/forums/showthread.php?t=2072495
18)
1995-1996 HD Sportster Parts Catalog pg 63
20)
1998 HD Sportster Parts Catalog pg 65
21)
1999 HD Sportster Parts Catalog pg 69
22)
2000 HD Sportster Parts Catalog pg 69
23)
2001 HD Sportster Parts Catalog pg 71
24)
2002 HD Sportster Parts Catalog pg 71
25)
2003 HD Sportster Parts Catalog pg 71
36) , 37) , 38) , 39)
xlforum.net/forums/showthread.php?t=1863121
40) , 41)
2004 HD Sportster Parts Catalog pg 67
42) , 45) , 47)
2005 HD Sportster Parts Catalog pg 71
43) , 46) , 48)
2006 HD Sportster Parts Catalog pg 71
44) , 49) , 50) , 51)
2007 HD Sportster Parts Catalog pg 71
52) , 53) , 59) , 61)
2008 HD Sportster Parts Catalog pg 71
54) , 60) , 62) , 68) , 69)
2009 HD Sportster Parts Catalog pg 109
55) , 75) , 76)
2010 HD Sportster Parts Catalog pg 103
56) , 77) , 87) , 88)
2011 HD Sportster Parts Catalog pg 103
57) , 78) , 89) , 94)
2012 HD Sportster Parts Catalog pg 103
58) , 79) , 85) , 90) , 95) , 96)
2013 HD Sportster Parts Catalog pg 115
63) , 70)
2010 HD Sportster Parts Catalog pg 105
64) , 71)
2011 HD Sportster Parts Catalog pg 105
65) , 72)
2012 HD Sportster Parts Catalog pg 105
66)
2009 HD Sportster Parts Catalog pg 111
67)
2010 HD Sportster Parts Catalog pg 107
73)
2013 HD Sportster Parts Catalog pg 117
74) , 80) , 86) , 91) , 97) , 100) , 102)
2014 HD Sportster Parts Catalog pg 81
81) , 92) , 98) , 101) , 103) , 104) , 107)
2015 HD Sportster Parts Catalog pg 81
82)
2010 HD Sportster Parts Catalog pg 109
83)
2011 HD Sportster Parts Catalog pg 107
84)
2012 HD Sportster Parts Catalog pg 107
93) , 99) , 108)
2016 HD Sportster Parts Catalog pg 81
105)
2015 HD Sportster Parts Catalog pg 83
106)
2016 HD Sportster Parts Catalog pg 87
109)
2016 HD Sportster Parts Catalog pg 85
110)
Folkie - xlforum.net/forums/showthread.php?t=738626
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