51 1197
S&S Cycle, Inc.
Instruction 51-1197
Copyright © 2006
by S&S Cycle, Inc.
All rights reserved.
Printed in the U.S.A.
235 Causeway Blvd.
La Crosse, Wisconsin 54603
Phone: 608-627-1497 • Fax: 608-627-1488
Technical Service Phone: 608-627-TECH (8324)
Technical Service Email: [email protected]
Website: www.sscycle.com
Because every industry has a leader
Installation Instructions: S&S® Performance Replacement
Cylinder Head Kit for 1984-’99 Big Twin Engines and
Harley-Davidson® Sportster® Models
S&S parts are designed for high performance, off road, racing
applications and are intended for the very experienced rider only. The
installation of S&S parts may void or adversely effect your factory
warranty. In addition such installation and use may violate certain
federal, state, and local laws, rules and ordinances as well as other laws
when used on motor vehicles used on public highways, especially in
states where pollution laws may apply. Always check federal, state, and
local laws before modifying your motorcycle. It is the sole and exclusive
responsibility of the user to determine the suitability of the product for
his or her use, and the user shall assume all legal, personal injury risk and
liability and all other obligations, duties, and risks associated therewith.
Statements in this instruction sheet preceded by the following words
are of special significance.
The words Harley®, Harley-Davidson®, H-D®, Sportster®, Evolution®, and
all H-D part numbers and model designations are used in reference only.
S&S Cycle is not associated with Harley-Davidson, Inc.
Before installing your new S&S part it is your responsibility to read and
follow the installation and maintenance procedures in these
instructions and follow the basic rules below for your personal safety.
● Gasoline is extremely flammable and explosive under certain
conditions and toxic when breathed. Do not smoke. Perform
installation in a well ventilated area away from open flames or sparks.
● If motorcycle has been running, wait until engine and exhaust pipes
have cooled down to avoid getting burned before performing any
installation steps.
● Before performing any installation steps disconnect battery to
eliminate potential sparks and inadvertent engagement of starter while
working on electrical components.
● Read instructions thoroughly and carefully so all procedures are
completely understood before performing any installation steps.
Contact S&S with any questions you may have if any steps are unclear
or any abnormalities occur during installation or operation of
motorcycle with a S&S part on it.
Means there is the possibility of injury to yourself or others.
Means there is the possibility of damage to the part or motorcycle.
Other information of particular importance has been placed in italic type.
S&S recommends you take special notice of these items.
All S&S parts are guaranteed to the original purchaser to be free of
manufacturing defects in materials and workmanship for a period of
twelve (12) months from the date of purchase. Merchandise that fails
to conform to these conditions will be repaired or replaced at S&S’s
option if the parts are returned to us by the purchaser within the 12
month warranty period or within 10 days thereafter.
In the event warranty service is required, the original purchaser must
call or write S&S immediately with the problem. Some problems can be
rectified by a telephone call and need no further course of action.
A part that is suspect of being defective must not be replaced by a
Dealer without prior authorization from S&S. If it is deemed necessary
for S&S to make an evaluation to determine whether the part was
defective, a return authorization number must be obtained from S&S.
The parts must be packaged properly so as to not cause further damage
and be returned prepaid to S&S with a copy of the original invoice of
purchase and a detailed letter outlining the nature of the problem, how
the part was used and the circumstances at the time of failure. If after
an evaluation has been made by S&S and the part was found to be
defective, repair, replacement or refund will be granted.
● Consult an appropriate service manual for your motorcycle for correct
disassembly and reassembly procedures for any parts that need to be
removed to facilitate installation.
(1) S&S shall have no obligation in the event an S&S part is modified by
any other person or organization.
● Use good judgement when performing installation and operating
motorcycle. Good judgement begins with a clear head. Don't let
alcohol, drugs or fatigue impair your judgement. Start installation
when you are fresh.
(2) S&S shall have no obligation if an S&S part becomes defective in
whole or in part as a result of improper installation, improper
maintenance, improper use, abnormal operation, or any other misuse
or mistreatment of the S&S part.
● Be sure all federal, state and local laws are obeyed with the
● For optimum performance and safety and to minimize potential
damage to carb or other components, use all mounting hardware that
is provided and follow all installation instructions.
(3) S&S shall not be liable for any consequential or incidental damages
resulting from the failure of an S&S part, the breach of any
warranties,the failure to deliver, delay in delivery, delivery in nonconforming condition, or for any other breach of contract or duty
between S&S and a customer.
● Motorcycle exhaust fumes are toxic and poisonous and must not
be breathed. Run motorcycle in a well ventilated area where fumes
can dissipate.
(4) S&S parts are designed exclusively for use in Harley-Davidson and
other American v-twin motorcycles. S&S shall have no warranty or
liability obligation if an S&S part is used in any other application.
S&S® Performance Replacement Stock Cylinder Heads
S&S® Stock replacement cylinder heads are designed to fit all Harley-Davidson® Evolution® big twin engines and Sportster® models. The
exterior dimensions of these heads are similar to Harley-Davidson® dimensions and require no additional clearancing when replacing
stock heads on engines installed in stock chassis. Customer will need to purchase proper installation kit.
NOTE: S&S cylinder heads are designed to work with all aftermarket roller rocker arm assemblies also.
The intake and exhaust ports are a cast to shape design that yields approximately 13% more flow than stock heads.
The valve train components are designed to improve flow and work with any present day fuel. Clearances are set for any S&S camshaft
with a lift of up to .630" without modification. If cams with lift of over .630" lift are to be used, head kits may be ordered with special
high lift, racing spring kits, allowing the use of cams of up to .660" lift.
One set of S&S Stock Replacement cylinder head assemblies complete with valves, valve springs, valve guide seals and
keepers installed.
Installation instructions.
NOTE: Other S&S products such as adjustable chrome moly pushrods, cam, Hydraulic Lifter Limited Travel kit, and Super
carburetor which may enhance the operation of S&S Stock Replacement cylinder heads may be purchased separately.
Installation of an S&S Stock Replacement cylinder head kit is easy and can be performed by any Harley-Davidson repair shop equipped
to do engine overhauls. No special tools other than those used in normal overhaul repair work are required.
Read instructions thoroughly before starting work. When they are completely understood proceed with installation.
Remove Components and Inspect Parts
Follow procedures outlined in appropriate Harley-Davidson® service manual to prepare motorcycle for top end service.
NOTE: Disconnect battery and drain all gasoline from gas tanks before doing any work.
Gasoline is extremely flammable and explosive under certain conditions and toxic when breathed. Do not smoke. Perform
installation in a well ventilated area away from open flames or sparks.
Remove gas tanks and all other parts required to perform top end service.
Remove carburetor, rocker covers, pushrods and pushrod tube assemblies, and cylinder heads
NOTE: Be careful not to introduce any dirt or other foreign material into crankcase during disassembly of engine.
Metal filings, dirt and any other foreign contamination in engine may cause premature wear and/or irreversible damage to
bearings and other internal engine components.
Thoroughly clean and inspect all parts that are to be reused. Any parts that show signs of wear or damage should be replaced.
Insufficient clearance between piston domes and cylinder heads or piston domes and valves will cause damage to pistons, heads
and/or valves. It is the engine builders responsibility to check for adequate clearance regardless of head and gasket combination.
Repeat procedure to check rear piston to cylinder gasket surface relationship.
S&S® Stock Replacement heads are designed to work with flat top pistons. If you attempt to use them with any other piston,
be sure to check for adequate clearance.
Coat piston skirts with engine oil and install cylinders.
Spin each head bolt down on its respective stud to be sure threads are clean and free of contamination.
Install head alignment dowels in cylinder. (Do not re-use any dowels that are damaged, or have flanges or an O-ring groove
machined into them.)
Place head gaskets onto cylinder and over head alignment dowels.
If the gasket fits close to the dowel pin and there is not room for an O-ring, do not install an O-ring.
If there is room for an O-ring, install one O-ring over each dowel per the note below.
NOTE: There are two sizes of alignment dowel O-ring available: .070" diameter O-rings are to be used with .045" thick gaskets. .0825"
diameter O-rings are to be used with .0625" thick gaskets.
Using thin O-rings with thick gaskets or thick O-rings with thin gaskets may cause oil leaks or possible ruptured head gaskets
around line-up dowels due to incorrect O-ring compression.
Ensure that the head gaskets and O-rings (if used) are correct for the application, then remove them and carefully clean head
and cylinder gasket surfaces with lacquer thinner or equivalent. Gaskets are to be installed clean and dry. Do not use gasket
sealing compounds on cylinder head gaskets.
Bolt heads on cylinders. Clean threads of head bolts and cylinder studs. Place one or two drops of oil on threads of each head
bolt just prior to final assembly to reduce friction and insure accurate torque readings. Tighten bolts in stages using crossing
pattern. If using S&S or stock crankcases, follow the the torque and sequence chart. See Figure 1. If using other aftermarket
crankcases, contact the manufacturer for recommended head bolt torque specifications.
Top View
Rear Head
Front Head
S&S® Crankcases
Stock Crankcases
Stage 1
8 ft-lbs.
7-9 ft-lbs.
Stage 2
18 ft-lbs.
12-14 ft-lbs.
Stage 3
Turn Additional 90°
Turn Additional 90°
Figure 1
NOTE: Light coating of oil on head bolt threads minimizes friction so torque values are not distorted. It cannot be emphasized enough
how important it is to do these steps carefully. Maintaining a good head gasket seal depends on it.
Improper torquing sequence and head bolt torque values may cause head gasket failure. Excessive torque values may cause
studs to pull out of crankcase.
Finish Assemble Top End, Install Carburetor and Replace Gas Tanks
Follow Harley-Davidson® factory procedures outlined in Harley-Davidson® service manual to assemble rocker cover components
and other parts that were removed for top end service.
Install rocker arm bases per Harley-Davidson® service manual guidelines.
Assemble rocker arms, pushrods and pushrod tube assemblies and adjust pushrods.
Install rocker covers using gaskets provided.
Install intake manifold, (using stock manifold, can use an S&S®) mounting flanges and O-ring seals. Be sure O-rings and flanges
are assembled in correct sequence. Use flange marked "F" on front head and flange marked "R" on rear. Slotted end of
mounting flange goes toward lower manifold mounting hole. Flat washer provided is used on slotted end of flange. Do not
tighten mounting flange screws.
Bolt carburetor and air cleaner assembly in place using carburetor instructions supplied from manufacturer.
NOTE: S&S cylinder heads are machined for use on all Harley-Davidson® Evolution® engines. Heads are drilled and tapped to accept 1⁄2"13 air cleaner mounting bolts used on 1992 big twin heads or 1⁄2"-13 threaded cylinder head vent fittings used on 1991 and later
Sportster® models and 1993-up big twins. For installation on 1984 to '91 big twins and 1986 to '90 Sportster® models, screw thread
reducing inserts, part 90-4026, in carburetor backplate mounting holes in cylinder heads. Surface of insert should be just slightly below
machined surface of head so backplate rests against head and not insert. See Picture 1. Insert (threadsert) will reduce hole to 5⁄16"-18
threads to accept stock 1984 to '91 air cleaner mounting bolts. Threadserts may be supplied with or without a thread locking
compound already applied to threads. Loctite® or equivalent thread locking compound should be applied sparingly to threads of those
not pre-coated during installation. Threadserts with preapplied thread locking compound should be installed in desired position and
left in place. IMPORTANT - Screwing threadsert in hole activates compound and locks it in position making it difficult to change after
compound has set up.
Picture 1
Installation of threadsert where it protrudes above air cleaner backplate mounting boss surface may damage air cleaner backplate.
Reassemble gas tanks and all other parts that were dissembled during preparation for top end service. Be sure there are no
gasoline leaks and that throttle opens and closes smoothly and snaps shut when released.
NOTE: Throttle must not bind and must snap shut to fully closed position when released.
If throttle does not return to fully closed position when released, it may inadvertently stick open possibly causing loss of control
motorcycle and personal injury to you or others.
NOTE: Fuel needle and seat assembly must completely shut off fuel supply entering bowl. Fuel line connections must not leak.
Unwarranted gasoline leaking by fuel inlet needle may flood engine causing damage to components.
Unwarranted gasoline leaks at fuel line connections and/or past inlet needle may flood engine and overflow on surrounding
area creating fire hazard.
Engine Break-In Procedure
Upon initial start-up, quickly check to make sure oil pressure is normal and no leaks exist. With minimal load on engine, ride
motorcycle at low speeds until cylinder head temperature reaches about 250°. Do not crack throttle or subject engine to any
heavy load during this period as head gaskets are susceptible to failure until heat build-up is completed. Heat build-up is
necessary to cause heads and cylinders to expand and seal. Improper initial engine start-up and break-in procedure may cause
head gasket failure.
Do not allow engine temperature to become excessive as permanent engine damage may result.
First 50 miles are most critical for new rings and piston break-in. Most engine damage will initially occur during this period.
Keep heat down by not exceeding 2500 rpm. Vary speed. Do not lug engine.
Next 500 miles should be spent running engine no faster than 3500 rpm or about 50-55 mph. Do not lug engine and continue
to vary speed.
Lugging or running engine prematurely at high rpms may result in damage to pistons and/or other engine components. S&S®
voids its guarantee if engine is not broken in properly.
For balance of first 1000 miles, speed can be run up to 60 to 70. Continue to run engine at all different speeds including lower
40-45 mph ranges.
1000 to 2000 miles—basically same procedures as before. You can be a little more liberal with rpm range. Avoid overheating
engine and putting any hard strain on engine (drag racing, trailer towing, sidecar operation).
2000 miles and up—have fun!
Performance Notes
Ignition Systems
● Stock electronic ignition systems are satisfactory, but usually will not allow modified engines to realize their full potential. The
S&S® Intelligent Spark Ignition system (IST) provides optimum ignition timing for any engine and works in all but turbocharged
and supercharged applications. It learns about the engine it is installed on, automatically senses the beginnings of spark knock,
and sets the advance curve and total advance for maximum performance under all conditions. If not using an S&S ignition, a
point type ignition system or an aftermarket high performance electronic unit is recommended. This allows flexibility in engine
timing not possible with stock ignition systems.
● Spark plugs - Use spark plugs that are compatible with the ignition system. If you are in doubt, most manufacturers can recommend
which plugs they prefer you use with their system. Dual plug installations in S&S Stock replacement heads are not necessary.
● Flywheels - S&S flywheels have timing marks that when located in the center of the timing hole position the pistons in the same
location before top center as stock Harley-Davidson® flywheels. Placing the mark to the right side of the hole or just entering
the hole advances timing almost 5°. Vice versa, if the mark is just leaving the hole, timing is retarded almost 5°.
● Timing - Tests conducted using S&S Stock replacement heads on big twins showed that best performance was achieved with the
ignition timing set at; 30°-32° total advance.
Once the engine is timed and operating, monitor it for excessive heat. Too much heat can mean that timing is set
incorrectly and should be adjusted to prevent engine damage.
Improper ignition timing may cause excessive engine heat which may damage pistons and/or other engine components.
● All S&S® test engines are run using S&S carburetors. S&S Super E and G carburetors are recommended for most applications
with the Super G being used more often on larger displacement, freer breathing engines with higher compression ratios.
Typically, engines equipped with S&S heads require the same or slightly leaner jetting than those engines fitted with stock
heads. Consult the carburetor jetting instructions for specific jetting recommendations.
● If another type carburetor is used, it must be made to run rich enough to operate properly and to prevent engine damage. If
you have a problem with another carburetor, S&S cannot help you and recommends you call the carb manufacturer with any
questions you may have.
● If the motorcycle is used exclusively on a drag strip where engine temperatures vary, slightly richer jets may be necessary for
best performance. Larger jets/richer mixtures will enable one to run a colder engine which is sometimes desirable. This is best
determined by experimentation.
● Carburetor jetting and spark plug color - While spark plug color may be used to help determine carburetor jetting, S&S
recommends that our instructions be used as primary jetting guide and that plug color indications be used only as secondary
aid. We have found that different brands of gasoline, gasoline additives, engine heat (due to ignition timing), and brands of
plugs and heat range used distort plug color drastically making plug reading difficult for the average tuner. Also, new plugs
usually require a road test of 10 miles or more to properly develop the color which means that quarter mile tests may not be
long enough and hence, not always a good indication of carb jetting. It is best to use proven spark plug combinations and to
consult the spark plug manufacturer if you have questions.
● Cams and exhaust systems can make some engines difficult to carburate. We have found that certain cams and exhaust systems
will cause poor performance at a specific rpm, and attempts to correct jetting for that specific level usually destroys carburetion
over the balance of the range.
A combination of cam overlap, reversion, and back pressure, or even lack of back pressure can cause mixture dilution at certain
engine rpms. This dilution will cause engine roughness or misfiring when engine is held in this range.
Exhaust Systems
● Drag pipes - While drag pipes can be used with good results to establish performance guidelines on the pre-1984 engines, they
are generally not recommended for 1984-up big twin motors in street applications. Big twin engines are easier to carburate
with muffled systems.
● Muffler systems: Most stock and many aftermarket exhaust systems are too restrictive and made exclusively for looks with little
consideration given to performance. A very good, economical street system for big twin engines consists of the stock header
pipes with the crossover tube and a set of low restriction mufflers. S&S offers a series of mufflers that can be used with stock
header pipes that work very well. This combination will typically produce more horsepower and torque than drag pipes in the
midrange. Since the midrange is where the vast majority of normal driving occurs, it makes this system ideal for the street.
● Gearing depends on the total weight of the machine and rider/s, the size of the engine, cam/s, exhaust system and type of
riding to be done. Most high performance engines, and particularly those with larger displacements, are capable of pulling
more gear. We suggest you break the engine in with stock gearing to minimize the load on the engine. After the engine
is broken in you will have a better feel of its potential and can change gearing accordingly.
● For those who wish to determine their final drive gear ratio the formula is as follows:
Engine Revolutions Per One Revolution of Rear Wheel =
(Clutch Sprocket*) x (Rear Wheel Sprocket*)
(Motor Sprocket*) x (Transmission Sprocket*)
*Number of teeth on each sprocket
● Generally speaking, big twin engines with the proper camshaft selection can operate using higher compression ratios with fewer
problems than their earlier counterparts. Keep in mind, though, that while engines with higher compression ratios make more
horsepower and perform better, they also tend to lose that performance edge faster, require more maintenance and start harder.
As a rule, we prefer to limit the compression ratio to no greater than 11 to 1 for engine combinations used in normal street
operation. A word of caution is in order. Before building an engine you may regret later on, carefully consider your riding needs,
riding style and overall performance objectives.
10. Flat washer - 3⁄8"
All (H-D® #6019) .....................................50-7051
1.575" diameter...................................90-2026
11. Head bolt assembly - Includes head bolt washer.
(Contact S&S for proper part number.)
Valve seats
Intake - 1.900" diameter...........................90-2138
Exhaust - 1.575" diameter ........................90-2028
12. Head bolt washer
.100" (10 Pack) .......................................50-7096
.250" (H-D® #6016) (10 Pack) .................50-7095
Valve guide - intake or exhaust
Standard (H-D® #18112-92) ....................90-2210
+.001" (H-D® #18130-83C) ......................90-2211
+.002" (H-D® #18133-83A) ......................90-2212
+.003" (H-D® #18131-83C) ......................90-2213
+.030" .....................................................90-2219
13. Exhaust port stud
19. Screw, manifold mounting
SH - 5⁄16"-18 x 1"
(H-D® #3201WA) (10 Pack) ...................50-0145
HH - 5⁄16"-18 x 1" (H-D® #3987,4017)
(10 Pack) .................................................50-0155
20. Washer, flat - 5⁄16" (H-D® #6016,6702)
(10 Pack) .................................................50-7069
21. Flange, manifold mounting
Front (H-D® #27009-86A) (5 Pack) ........16-0600
Rear (H-D® #27010-86A) (5 Pack) .........16-0601
(H-D® #16715-83) (5 Pack)......................50-1028
Valve spring shim - 1984-up S&S® springs
14. Lock washer - 5⁄16" (H-D® #7041)
(10 Pack) ..................................................50-7077
22. O-ring, manifold
All S&S manifolds for Harley-Davidson®
15. Nut, HH - 5⁄16" -24 (H-D® #7833)
(10 Pack) .................................................50-5048
23. Head gasket, All S&S heads for Evolution® engines
(No O-rings required.)
16. Exhaust pipe gasket -
.015" (5 Pack) ........................................50-7161
.030" (5 Pack) ........................................50-7162
Head mount bolt - 3⁄8"-16 x 1 1⁄4"
All (H-D® #4716) .....................................50-0168
Cylinder head - 1984-99 big twin style
1.900" diameter ...................................90-2139
31⁄2" Bore
.045" thick (H-D® #16770-84C) (10 Pack) .93-1024
(H-D #65324-83) (10 Pack)....................93-1072
17. Thread conversion insert
⁄2"-13 to 5⁄16"-18........................................50-8151
Valve guide seal - intake or exhaust – 1984-up
(H-D® #18001-83A) (5 Pack) ..................90-2195
.0625" thick (H-D® #16770-84B) (10 Pack)93-1051
3 5⁄8" Bore
.045" thick (10 Pack)..............................93-1052
18. Intake manifold
(Reference manufacturers information.)
Valve spring kit, 1984-up
.640" lift - steel top collars .....................90-2077
.062" thick (10 Pack) ..............................93-1053
Keeper, valve spring, intake/exhaust
(8 Pack) ...................................................50-7160
All reference to Harley-Davidson® part numbers is for identification
purposes only. We in no way are implying that any of S&S® Cycle’s products
are original equipment parts or that they are equivalent to the
corresponding Harley-Davidson® part number shown.
Because every industry has a leader
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