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EVO: Engine Mechanicals

Timing Inspection Hole

Sub-Documents

Motor Mounts

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

Cylinder Mounting Studs

Weakest cylinder mounting stud holes in the case. 1)

Cam / Gearcase Cover

Sub Documents

#2 Cam - Cover Seal (86-03)

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)

Primary Cover

Sub-Documents

Shifter shaft Seal

This is a shifter shaft seal on a 1998 1200S primary cover.



Engine Case / Sump Drain Plugs

Sump drain on 04 model 4)

Flywheel Assembly

Year Model 5)Flywheel
Assembly
Connecting Rod
Assembly
Crankpin
Early 1986 Models
E1986 XLH88323905-8624275-8623960-80A
E1986 XLH110023900-8624275-8623960-80A
Late 1986-1990 Models
L1986 XLH88323905-86A24275-86A23960-80A
1987 XLH88323905-8724275-86A23960-80A (std)
23948-87 (.001“ O.S.)
23949-87 (.002” O.S.)
1988 XLH88323905-88
1989-1990 XLH88323905-88A
L1986 XLH110023900-86A24275-86A23960-80A (std)
23948-87 (.001“ O.S.)
23949-87 (.002” O.S.)
1987 XLH110023900-87
1988 XLH120023900-8824275-86A23960-80A (std)
23948-87 (.001“ O.S.)
23949-87 (.002” O.S.)
1989-1990 XLH120023900-88A
1991-1999 Models
1991-1994 XLH88323905-8924275-86A23960-80A (std)
23948-87 (.001“ O.S.)
23949-87 (.002” O.S.)
1991-1994 XLH120023900-9024275-86A23960-80A (std)
23948-87 (.001“ O.S.)
23949-87 (.002” O.S.)
1995-1999 All Models23905-89A24275-86A23960-80A (std)
23948-87 (.001“ O.S.)
23949-87 (.002” O.S.)
2000-2003 Models
2000-2003 All Models23905-00
23905-00A
Not Sold
Separate
Not Sold
Separate
2004-up Models
2004-2005 All Models23905-04Not Sold
Separate
Not Sold
Separate
2006-2009 All Models
(Except XR1200)
23905-04ANot Sold
Separate
Not Sold
Separate
2010-2019 All Models
(Except XR1200/X)
23905-04BNot Sold
Separate
Not Sold
Separate
2009-2013
XR1200 / XR1200X
23999-08Not Sold
Separate
Not Sold
Separate

95-99

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)

00-03

Flywheel assembly 23905-00 6) Flywheel assembly 23905-00A 7)

Flywheels

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. 8) 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).

95-99 Flywheels 9)
L1986-up crank pin boss washer (6508) 10)


Crank Pin

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

L87-03 crank pin 11)

2004-Later:
The sprocket shaft nut torque for 2004 & later Sportsters and 2003 & later Buell XB models has been changed. 12)
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.

Connecting Rods

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).

Pinion Shaft

Removing / installing the pinion shaft nut

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. 13)
So this is one of those situations where it's best to use the proper tool. 14) The pinion nut takes a 15/16” wrench size.

90 and Prior Models (4 Speed)

Homemade Pinion Gear / Removal / Installation Tools 15) Homemade pinion gear press 16) Pinion Gear Puller 17)
Large fender washer cut into a “C” shape and a gear puller
Homemade Pinion Gear Puller 18)
3/8“ stainless steel plate with 20° spokes (for 18 teeth),
sawed initial groove to depth and widened it with files
Homemade pinion gear locking tool for '89 models 19)

91 and Up Models (5 Speed)

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

  • You can use a 15/16” 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.

20) 21)

  • 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 22) 23)

24) 25) 26)

  • 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. 27)
    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.

28) 29)

Pinion Shaft Runout

Attach a scrap piece of metal to the outside of the gearcase and position a gauge holder on it so it won't move while turning over the engine. 30)
Install a dial gauge on the holder with the pointer on
the pinion shaft. Find the lowest spot while turning
the engine over and 'zero' the indicator. 31)
This setup is made with a piece of angle iron for the magnetic base to stand on 32)
This gauge post is threaded into a cover mount hole. 33)

Crankshaft Seal

Here is a trick to hold the spring in place to stop it popping off while you are fitting the seal. 34)
Before fitting it, pack some grease around the spring in the seal groove. You only need a small amount.


1) , 2) , 3) , 20) , 24)
photo by Hippysmack
5)
1986-2019 HD Sportster Parts Catalogs
9) , 10) , 11)
photos by Hippysmack
12)
HD Tech Tip #211 dated September 16,2005
23)
Grindlock 91-99 & Grindlock 2000, designed by XLFORUM member, “~Grind~” and Built by Hammer Performance ((aswracing of the XLFORUM http://xlforum.net/forums/showthread.php?t=1618841
30)
photos by anachris of the XLFORUM
31)
photo by Grind of the XLFORUM
32)
photos by dezzertrat of the XLFORUM http://xlforum.net/forums/showthread.php?t=1860581
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