EVO: Engine Mechanicals


Cam Specs - OEM & SE


  • 86-87 “T” cams will not work on 88 and up engines.
  • 88-90 “C” cams will retrofit to 86-87
Cam GrindLiftOpensClosesDurationLiftOpensClosesDurationOverlap
T 1).278“1°ATDC42° ABDC221°.250”40° BBDC18° ATDC238°17°
C 2).278“1°ATDC42° ABDC225°.280”42° BBDC3° ATDC225°

Comparing OEM and Andrews Cam Grinds

These figures are from the Sportster Evolution Cams PDF from Andrews Products. 3)

@ .053“ Lift
CLDuration @
.053” Lift
Durarion @
.020“ Lift
Max LiftTDC Lift

I/E = Intake/Exhaust — CL = Centerline

Thanks to Maxeffort of the XLForum for the following Flywheel Degree Charts of these various cams.4)

The measurements are based on the .053 lift specs. Also, take note that the predominance of the intake valve opening occurs on one rotation of the flywheel and the predominance of the exhaust valve opening occurs on the next rotation of the flywheel. It takes two full rotations (720°) of the flywheel to complete the four-cycle process. (This view of the flywheel would be from the right side of the engine.)

Removing / Installing Evo Cams

Sub Documents

EVO Cam and Pinion Gear Sets

  • 86-99 - Matched cam gear set includes pinion gear and gearcase cover.
    • Cam gears are individually matched to each specific gear cover using computer modeling in a controlled environment. 5)
    • Cams are colored coded with a colored dot.
    • Factory gearcase covers were also color coded on the inside with a color dot at each pinion and cam gear location.
    • This allowed for separate colored gears to be factory assembled (and later replaced) using gears optimized for the lowest gear whine and rattle.
      The dealer had to match the cover and gear colors for replacement covers.
  • For 2000-03 the options were:
    • Select full matched cam gear sets w/ pinion gear,
    • or choose only #2 cam w/ pinion gear,
    • or choose only the pinion gear,
    • or choose the gearcase cover (now sold separately).
  • For 2004-later, the options were:
    • Select full matched cam gear sets w/ pinion gear,
    • or choose only the pinion gear,
    • or choose the gearcase cover (sold separately).
Year Models & Included Parts Cam
Cam #1 Cam #2
Cam #2
Cam #3Cam #4Pinion
Cam #2)
86-87 6)(25488-86) All
cams, pinion gear and cover
88-90 7)(25488-88) All
cams, pinion gear and cover
91-94 8)(25488-89) All
cams, pinion gear and cover
95-97 9)(25488-89A) All except '96 & '97 1200C
cams, pinion gear and cover
96-97 10)(25483-96) 1200C
cams, pinion gear and chrome cover
98-99 11)(25448-89B) Std/Hug/1200
cams, pinion gear and polished cover
(25483-96A) 1200C
cams, pinion gear and chrome cover
(25491-98) 1200S
cams, pinion gear and silver cover
00 12)(25193-00) all except 1200S
cams and pinion gear (no cover)
(25190-00) all except 1200S
Only #2 cam and pinion gear
(25194-00) 1200S
cams and pinion gear (no cover)
(25191-00) 1200S
Only #2 cam and pinion gear
01-03 13)(25193-00A) all except 1200S
cams and pinion gear
(25194-00A) 1200S
cams and pinion gear
04-06 14)(25193-00B) 883/883C
cams and pinion gear
(25194-00B) 1200C/1200R
cams and pinion gear
07-17 15)(25194-06) all except XR1200/XR1200X
cams and pinion gear
09-12 16)(25271-08) XR1200/XR1200X
cams and pinion gear

Cam Gear Changes

  • The #2 “W” cam may or may not have a provision for a timing cup after 03. 17)
    • If you intend on installing 04-up “W” cams in 03 and prior engines, look at the end of the #2 cam.
    • If it does have a provision for a timing cup, they'll work for prior year applications.
    • But, you'll have to either update your pinion gear, or use a press to swap your #2 cam's drive gear.
    • For 03 and prior year engines, it needs a drilled and tapped hole in the middle of it and the timing cup notch.
    • Below (L), you can see the notch on the cam on the right very easily.
  • The #2 cam gear changed from '99 to '00 and again in '01.
    • The '99 version has coarse teeth on both driven & drive gears.
    • The '00 has a high contact (HCR) driven gear with a coarse tooth drive gears (along with the other cam gears). The pinion gear has HCR teeth as well.
    • For 2001, the #2 cam gear has both the driven gear & the drive gear using the HCR type teeth (as do the other cam gears).
    • Below (Right Pic), compares the '99 #2 cam gear (left-side) and the '01 style #2 cam gear (right-side).

18) 19)

Tappets (lifters)

Hydraulic Lifters


There was a running change to new style hydraulic lifters in 1986 for Sportsters. 20)
They were the same as those used in 1340cc engines beginning in the 1986 model year.
This change was made to allow for one component to service the entire product line.
Beginning with Sportster crankcase numbers;
883: 1786 127 043
1100: 1886 127 001
The new lifters were identified with the presence of two notches opposite each other in the pushrod socket.

Checking Lifter Pre-load

Hydraulic lifters self-adjust over about a .100” range, from .050“ preloaded to .150” preloaded. 21)
They'll actually work outside that range but they might make noise, so it's best to stay in that range.

  • Measure at the rocker box how much the lifter will get preloaded at the rocker box. 22)
    • Put your pushrods in place (remember, the longer one goes on the exhaust).
    • Set the gasket and rocker box on top, and start the four big screws only.
    • Finger tighten the left (spark plug) side.
      (while making sure the right side is resting with the upper pushrod ends sitting in the cups on the rocker arms)
    • Now take a simple caliper and measure how much gap you have between the rocker box and the rocker box gasket, as shown in the photo below.
    • This won't be an exact answer, but it'll be pretty close.
      Remember, you'd like to see the plunger preloaded about .100“, but anywhere between .050” and .150“ should work.
      You can order pushrod lengths that are longer or shorter than your stock pushrods by the amount it takes to achieve .100” of lifter plunger preload.
      If you don't have a caliper to measure your stock pushrod lengths, the information is available in most factory service manuals.

The lifter plunger should be preloaded between .050 and .150. Make the measurement if you're not sure.

Oil feed to lifters

A hydraulic lifter self-adjusts within a certain range. 24)
In other words, if your pushrods are too long, the lifter automatically shortens, and if the pushrods are too short, it automatically lengthens.
The hydraulic lifters used in HD motors have about .200 of plunger travel.
As long as it's preloaded between about .050 and .150, it adjusts itself properly.
So in other words, there's about a .100“ range of pushrod length.
The lifter will automatically adjust it's length to make it all work properly.

91 and up engines have a horizontal passage on the top of the cam box that is fed oil from the filter pad.
This horizontal passage feeds into the lifter bores.

91-99 engines have a single passage in that top
area, the tappets are connected by internal
passages from this small cavity.
On 2000 and up engines, oil travels to each lifter
individually from this cavity. 25)

86-90 models

Per HD Service Bulletin M-030A;
Beginning with crankcase #1786 127 043 (883cc) and 1886 127 001 (1100cc), new style hydraulic lifters were installed at the factory.
New style lifters can be identified by the presence of notches in the pushrod socket.
Click here to go to the service bulletin page where you can download the service bulletin.

  1. A piece of wire can no longer be used to drain lifter during installation.
  2. After push rod lengths have been measured and the correct length push rods selected, remove lower rocker boxes.
  3. Rotate engine so both lifters from the cylinder being serviced are on the base circle (lowest position of the cam).
  4. Install push rods and push rod tubes. Install new gaskets under lower rocker box.
    Place lower rocker box assembly (with rocker arms and shafts) in position.
    Place push rods in rocker arm sockets.
  5. Slowly snug all rocker box fasteners in small increments (one turn at a time).
    Use a cross pattern on the four large bolts that fasten the lower rocker box to head.
    This will bleed the lifters. Tighten fasteners to the correct torque. Refer to the 1986 XLH Service Manual for the proper tightening sequence.
    CAUTION, Do not turn the engine over until both push rods can be turned with fingers to avoid damage to push rods or rocker arms.
  6. Repeat Steps 2 through 5 for other cylinder

26) 27)

91-99 Lifters

91-99 engines have AMC-Mopar style lifters (.903” diameter). 28)

91-99 lifters (18526-89A) 29)

91-99 Anti-Rotation Pins

4 - screws (884)
4 - washers (6099)
2 - pin plates (36804-89)
4 - O-rings (11176)
4 - anti-rotation pins (18532-89)

Torque: 80-110 in. lbs. (9.0-12.4 Nm) 30)

91-99 anti-rotation pin hardware 31)
App. pin dims 32)
App. pin plate dims 33)
Slide the pins in the holes, install the O-rings over the pins. 34)
Then install the plate and torque to 80-110 in lbs. 35)

2000 and Up Lifters

2000 and up have GM/twin cam style lifters (.842“ diameter). 36)

Lifter from an 02 XL883 37)

00-05 Lifter Ant-Rotation Screws

4 - anti-rotation screws (18532)

This is the redesigned version of the anti-roll pins.
Comprised of a single pin for each lifter as before (4 in all).
However, this is a one piece design that is threaded into the case with no holding plate.

Torque: 55-65 in. lbs. (6.2-7.3 Nm) 38)

00-05 anti-rotation screws 39) App dims (photos by Hippysmack))
End of screws run up into the case. 40)

06-Up Anti-Rotation Device

2 - Anti Rotation Device blocks (18505-06)
The ARD is a flexible piece of plastic that is designed to flex in operation to allow for an imperfect lifter bore location. 41)
It is designed for lifters that have a flat cut on each side.

These work OK for stock cams.
But if you're upgrading to bigger cams, anything more than .600 lift has too small a base circle. 42)
(and they will nearly drop out of the ARDs and they can also spin away from them)
The big issue is that they turn sideways with the roller not turning on the cam lobe.
(which can heat up and destroy the roller and the cam lobe)

ARD block 43) ARD block installed 44)

Pinion Gear

45) Frame mount Evos 1986-2003 do not list a part number for the pinion gear and it appears the pinion gear is part of the (cam gear set).
The 88-99 pinion gear has a coarse tooth pitch.
The 2000-up pinion gear has a fine tooth pitch.

Pinion Gear Part#Year Models
24047-002004-2016 All Models

XL Pinion Gear Color/Size Info here: http://xlforum.net/forums/showthread.php?t=1963918

Possible 91-up woodruff key failure notice:
The woodruff key on the pinion shaft has ben subject to shearing.
There is a bronze oil pump gear available which is considered an upgrade but that won't stop the key from shearing.
Read more about the oil pump drive gear failure and upgrade here in the Sportsterpedia.
What happens is the crank develops a little run-out (especially when the power level is raised). 46)
This causes the teeth of the steel oil pump drive gear to wear badly on one side.
Generally, 180° from the worn teeth (front of tooth pitch) you'll see almost no wear at all so you have to inspect all the way around the gear (rear tooth pitch).
If you see them sharpening like the above photo, you're on borrowed time.
When one of these steel gears fails, it's really ugly and makes a mess and can damage a lot of other things as well.
The bronze gear solves the problem nicely though. It's a Buell piece that came out in 2006.
This was a much worse problem on Buells due to the higher power levels.
But at 65hp, it's not nearly so big of an issue, so HD never bothered to put them in XL's probably due to cost.
It's a good upgrade when hopping up an XL and it's cheap insurance against a catastrophic failure.

It's very important to hold the crank still from this side (not the primary side) when torquing the pinion nut.
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.
Now, with respect to the key shearing, it's a very common issue particularly when heavy valve springs are used.
The caption describes the fix, Loctite red and 70ft-lbs instead of the factory specified 35-45ft-lbs. You won't have this issue again. 47)
You'll need a tool to lock the pinion gear for removal or installation. See tool options in the REF section of the Sportsterpedia.

Timing Cup (Rotor)

Timing cup bolt thread size: #10×32
Wrench size: 5/16”
Torque: 43-53 in/lbs 49)
Use Loctite 242 (blue) on the bolt threads 50)
Installing timing cup bolt on a 98 1200S 51)

Cam Bushings

  • The cam bushings get their oil from the fling off of the cam gears and drain back from the top end down the pushrod tubes that puddles in at depressions in the castings where the cam bushing slots are aligned. So basically they are drip fed. Also the cam bushings on the case side are open to the crank behind them, and probably get splash there too. 52)
  • Worn bushings can cause excess backlash. 53)
2010 1200X Inner Cam Bushings (broken teeth on oil pump gear) 54) 2010 1200X Cam Cover and Bushings 55)

1) , 2)
MMI Evolution Cam Specs dated 10/5/92
5) , 53)
1986 HD Dealer Sportster FSM pg 3-45
6) , 7)
87-88 HD Sportster Parts Catalog pg 17
91,92,93,94 HD Sportster Parts Catalogs
95 HD Sportster Parts Catalog
95-96 HD Sportster Parts Catalog pg 15
98 HD Sportster Parts Catalog pg 15
00 HD Sportster Parts Catalog pg 17
01 HD Sportster Parts Catalog pg 19
04 HD Sportster Parts Catalog pg 17
15) , 16)
07 HD Sportster Parts Catalog pg 19
1986-1990 HD Sportster FSM pg 3-44
photo by aswracing of the XLFORUM http://xlforum.net/forums/showthread.php?t=113818
26) , 27)
photo by xtremraptor of the XLFORUM
“A 4 liter V8 eater” of the XLFORUM http://xlforum.net/forums/showthread.php?t=1611832
98 HD Sportster FSM pg 3-5
31) , 32) , 33) , 34) , 35)
photos by Hippysmack
photo by Scuba10jdl of the XLFORUM http://xlforum.net/forums/showthread.php?t=1706033
04 HD Sportster FSM pg 3-7
photo by Hoppysmack
photo by chris_b_owens of the XLFORUM http://xlforum.net/forums/showthread.php?p=5042968
From HD Parts Catalogs 2004 pg 17, 2005 pg 19, 2006 pg 19, 2007 pg 19, 2008 pg 19, 2009 pg 25-27, 2010 pg 25-27, 2011 pg 25-27, 2012 pg 25-27, 2013 pg 29-31, 2014 pg 17, 2015 pg 19, 2016 pg 19
49) , 50)
1998 XLH FSM pg 7-56
photo by Hippysmack
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