• 91-03 Timing inspection hole and plug pics and app. dims
• 1986-2003 Sportster Engine Case Identification

Click here for Engine Mounts in the Evo Suspension section of the Sportsterpedia.

• Removing the Rocker Boxes
• Removing, Inspecting and Installing the Cam Cover

Seal number (11124):
This surrounds and seals #2 cam when the cover is installed.
See also Removal / Installation of the #2 cam cover seal in the Sportsterpedia.

This side faces out. 2)	This side faces #2 cam shaft. 3)

• Removing 91-03 Primary Cover

Navigate to the appropriate year model transmission pages in the Sportsterpedia for removal/installation.
Part numbers:
2003 and earlier (37101-84)
2004-2005 (37101-84A)
2006-up (37107-06)
There is a steel bushing pressed into the bore in the cover. The seal installs on the outside of the bushing with a light press fit.
The seal can be removed/installed without removing the primary cover.

Shifter shaft seal on 1998 1200S primary cover.
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Shifter shaft seal on 2006 1200R primary cover.
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The flywheel assembly doesn't really press into the left case half, that's a misconception that a lot of people have.
There are two bearings that get pressed onto the sprocket shaft, and the left case half is sandwiched in between those two bearings.
So it's not the crank itself that's pressed in, it's two bearings that are pressed onto the crank.
(positioned as one inside and one outside of the left case (inner and outer case positions). ¹⁰⁾

Proper assembly of the lower end requires special tools to remove / install the bearing races into the case halves. ¹¹⁾
Plus you need a puller that can get the inner bearing off to replace it.
And you need to be able to accurately measure the pinion shaft bearing races to a ten-thousandth (.0001”) to select the right replacement size bearing.
(which means snap gauges and a couple different sized .0001“ reading micrometers)
Plus you need to rig up a dial indicator to check your flywheel end play.
And if you've already pressed against the flywheel assembly to remove it, it really ought to be put in a truing stand and make sure it's still straight.
Also, once it's all together, the sprocket shaft seal ought to be put on with the correct tool.
The tool puts it in square and sets the depth correctly.

Left Side Bearing Assembly: ¹²⁾

• The inner bearing goes on the crankshaft before installing it through the bore in the left case.
  And it will remain on the shaft once the shaft is removed from the left case.
  It's corresponding inner race (Timken bearing outer race) is a cone shaped race that's pressed into the inside of the left case.
  It will also remain in it's place when the flywheel assembly is removed.
  
• There is a bearing spacer that resides between the inner and outer bearings that separates the bearings and sets the preload between the two.
  It basically controls how much gap is left between the bearings and the case half (actually the races which are pressed into the case half).
  The bearing spacer (shim) is available in sizes from .098” to .114“ in steps of .002”.
  It's thickness is sized (selected) to set the flywheel end play. The end play spec is .001“ to .005”.
• There is also a bearing race spacer. This spacer is a thick piece of steel that's sandwiched between the inner and outer bearing races.
  It fits into a notch that's machined into the cases. It has a gap that needs to be pointing straight up as there's an oil hole there where crankcase oil bleeds down into the bearing area.
  It will most likely (should) stay in the middle of the cases once the flywheel assembly is removed.
• The left case outer bearing race, like the inner race, this is a cone shaped race that's pressed into the case.
  It will most likely stay in the case once the flywheel assembly is removed.
• The outer bearing, same as the inner bearing, is pressed onto the crankshaft and will have to be removed before the flywheel assembly comes out.
  Then it'll have to be pressed back on when the flywheel assembly is installed.
  
• There is another spacer that sits directly under the front primary sprocket and holds it away from the outer bearing.
  The seal rides on this spacer. Don't forget it.
• Even though both bearing outer races are installed into the case half with a press, you really can't put the sprocket shaft bearings on with a press.
  Pressing against the flywheel assembly is a really bad thing to do, it'll knock it out of true.
  There's a special tool for pushing those bearings onto the shaft. It threads onto the end of the shaft, so it never presses against the wheels at all.

Right Side Bearing Assembly: ¹³⁾
The pinion shaft just slides into the right case. Oil everything up first though.

• The pinion bearing is available in four different sizes.
• The outer race for the pinion bearing is pressed into the right case.
• You have to precisely measure the I.D. of the outer then measure the O.D. of the race that's on your pinion shaft.
• Then there's a table in the service manual that shows you which of the four different available pinion bearings to use based on those two measurements.

The same flywheel set was used in all Sportsters 95-99.
Sold as a unit: part number (23905-89A) consists of the flywheels, shafts and rods.
Each flywheel casting number (23931-88A)
Connecting rod set: part number (24275-86A)
Front connecting rod casting number (24321-83)
Rear connecting rod casting number (24320-83)
Rod bearing set (24354-87A)
Rod bearing race - front (2)-(24341-52A)
Rod bearing race - rear (2)-(24352-52A)
Piston pin bushing std (2)-(24331-36), .01“ O.S. (24332-36
Crankpin std (23960-80A), .001” O.S. (23948-87), .002“ O.S. (23949-87)
Crankpin boss washer (2)-(6508)

The OEM Flywheel assembly (23905-00) was factory installed in all Sportsters 2000-2003.
That's to say the entire assembly part number is the same from 00-03.
However, the rods in the 2000-2002 assemblies are reportedly thicker than the 2003 assembly. ¹⁵⁾

The entire assembly was sold as a unit with no published part numbers for it's individual parts.
To date, we have no pics or casting numbers on the 00-02 rods for comparison.
Rod bearings and races, crankpin and even the shaft nuts were not mentioned in the parts catalogs.

Piston Pin bushing, standard (24331-36), 0.01” O.S (24332-36)
Inner bearing ring (24658-87)
Retaining ring (11177A)

Flywheel assembly 23905-00 16)	Flywheel assembly 23905-00A 17)

The original OEM Flywheel assembly (23905-00) was factory installed in all Sportsters 2000-2003.
However, the rods in the 2003 assemblies are reportedly thinner than in the 00-02 assembly and carry -02 casting numbers. ¹⁸⁾
So the original 2003 flywheel version appears to be a one year only version.

Entire assembly was sold as a unit with no published part numbers for individual parts for the assembly.
Rod bearings and races, crankpin and shaft nuts were not mentioned in the parts catalogs.

• The assembly in the pics below came from a 2003 883R:
  • Front connecting rod casting number (24225-02)
    
  • Rear connecting rod casting number (24224-02)
    

Piston Pin bushing, standard (24331-36), 0.01“ O.S (24332-36)
Inner bearing ring (24658-87)
Retaining ring (11177A)

Flywheel assembly 23905-00 19)

Flywheel assembly 23905-00 20)

Late 1986 flywheels and crankpin bearing changes.
Information from Technical Service Bulletin #M-927. Click here to see the actual bulletin from this page in the Sportsterpedia.
Beginning with crankcase numbers 883cc (1786 083 003) and 1100cc (1886 090 012), a new (F.A.G.) crank pin bearing set and revised flywheels were installed at the factory.
The new crank pin bearing set (using the existing crankpin P/N) consists of three bearings in a package. Early production engines were assembled without thrust washers.
L1986-later production flywheels had thrust washers staked into a counter-bore in the flywheels. The L86 crank pin bearing set retrofits earlier models.
However, the new bearings require a stepped flywheel thrust washer to provide clearance for the wider bearing cages.
You will select the correct thrust washer for your particular assembly and machine off the raised lip in the area of the flywheel thrust washers' I.D.
This lip must be machined off or you will crush the bearing cage as you assemble and torque the crankpin nuts.
See Tech Tip #14, Instruction Sheet #J00022 and Instruction Sheet #J00025 in the Sportsterpedia for more information.

The L86 XLH883 flywheel assembly is (23905-86A) and the L86 XLH1100 flywheel assembly is (23900-86A).
There were new crank pin bearing clearances also.
The new crank pin bearing set packages were color coded with either a red or a blue identification. This color coding is used by the bearing manufacturer only.
The color coding DOES NOT indicate size selection for crank pin bearing replacement.

1989 flywheel changes.
Information from Technical Service Bulletin #M-971. Click here to see the actual bulletin from this page in the Sportsterpedia.
Beginning June 1, 1988, flywheels forged from a micro-alloyed steel went into production. Part numbers and color codes of assemblies with the new material were changed.

1991-1994 Flywheels.
From '91 to '94 the Crankshaft/Flywheel was balanced according to the engine size, either for 883 pistons or 1200 pistons. From 1995-later, the flywheels are balanced to be between the weight of the 883 & 1200 pistons. ²¹⁾ This is one reason why riders would use Wiseco pistons in early (pre-2004) 883 to 1200 conversions - the Wiseco 1200 piston & pin was closer to the weight of the 883 combination rather than the stock 1200 piston & pin from HD.

1995-1999 Flywheels.
Flywheel assembly part number (23905-89A).
Each flywheel casting number (23931-88A).

2000 Flywheels:
There are no timing marks on the wheels for any of the rubber mounts. ²²⁾
Nor is there a timing window (on the case) to look through to see the mark that's not there.
And for that matter, there's no way to change the timing, even if you had a window to see the mark that's not there.
The only way to change the timing on a rubber mount is to use an aftermarket ignition that gives you control, through dials and/or a programming kit.
And even doing that, there's no way to measure it, you just have to trust that it's delivering the timing you're telling it to.

95-99 Flywheels 23)

L1986-up crank pin boss washer (6508) 24)

Crank pin (23960-80A) used from L1981-2003.

L87-03 crank pin 25)

2004-Later:
The sprocket shaft nut torque for 2004 & later Sportsters and 2003 & later Buell XB models has been changed. ²⁶⁾
The torque has been increased from 190-210 ft-lbs. to 240-260ft-lbs.
Remember to clean the threads and generously apply LOCTITE Threadlocker 262 (red) onto the threads of engine sprocket shaft and use a sprocket locking tool.
Some examples of sprocket locking tools are here in the tools section of the Sportsterpedia.

Rod set (24275-86A) includes bearings, crankpin and nuts.
Below are pics of just the rods off a 1998 1200S model.
The part numbers cast into the rods are front (24321-83) and rear (24320-83).

Below is the rod set known to be fitted to at least 2003 model Sportsters.
Front casting number (24225-02)
Rear casting number (24224-02)

^{27) 28) 29)}

To remove or install the pinion gear nut,
You'll need to lock the pinion gear from moving while turning it.
It's very important to hold the crank on the pinion side with an appropriate pinion locking tool whenever you take the pinion nut off or put it on.
If you hold the crank still from the primary side (or by putting the bike in gear and holding the brake),
The twisting torque applied to the pinion nut gets transmitted through the crank, from one side to the other.
The crank pin is not designed to resist much twisting force.
You'll risk scissoring the crankshaft (knocking the crank out of true), which requires a full tear-down to fix. ³⁰⁾
So this is one of those situations where it's best to use the proper tool. ³¹⁾ The pinion nut takes a 15/16” wrench size.

See also in the Sportsterpedia:
Oil Pump Drive Gear
Origin of the Grindlock Tool

• You can use a 15/16” 6 point wrench or deep well socket to remove / install the pinion gear nut.
• The Grindlock Pinion Shaft Locking Tool engages for the full depth of the pinion gear for max. strength.

^{37) 38)}

• Due to a change in the pinion gear in 2000, there are 2 different versions of this tool:
  (L) - (91-99) year models & (R) - (2000 to present) year models ^{39) 40)}
  

^{41) 42) 43)}

• Once the pinion shaft nut is removed, the pinion gear may or may not slide off by itself.
  You can use a gear puller to remove it if it is stuck on.
  
• It's very important to hold the crank still from the cam side (not the primary side) when torquing the pinion nut. ⁴⁴⁾
  If you for example put the bike in gear and hold the rear brake and torque on the nut, you run the very real risk of knocking the crank out of true.
  It's not designed to transmit torque from one side to the other and it tries to twist the crankpin connection.
• In respect to the key shearing, it's a very common issue particularly when heavy valve springs are used.
  However, it shouldn't be the one thing that keeps the gear from spinning. The clamp load should do that.
  The caption in the second pic below describes the fix:
  Loctite red and 70ft-lbs instead of the factory specified 50ft-lbs. You won't have this issue again.
  

^{45) 46) 47)}

Check to see if your crank is out of true. See Measuring Pinion Shaft Runout in the REF section of the Sportsterpedia.

Here is a trick to hold the spring in place to stop it popping off while you are fitting the seal. ⁴⁸⁾
Before fitting it, pack some grease around the spring in the seal groove. You only need a small amount.

Crankshaft Seal (35151-74A) 49)