S&S Worldwide Motorcycle Accessories User Manual

Page 2

INTRODUCTION

Installation of an S&S

Harley-Davidson

Sportster

model 3

⁄

bore stroker Sidewinder

Kit is easy and can be performed by

any Harley-Davidson

repair shop equipped to do complete

engine overhauls.

NOTES:
●

To make installation of S&S Sidewinder series 3

⁄

" bore kits

easier, S&S has designed several Special Tools worth
considering. They are:
Part 53-0002 - Connecting Rod Checking Pin - helps check
piston alignment in cylinder bore.
Part 53-0020 - Degree Wheel Kit - used to check and set
ignition timing and to check cam timing. This kit can also
be used to check crankcase breather gear timing in big
twin engines.
Part 53-0006, 53-0007 and 53-0008 - Crankcase Boring
Fixture and Crankcase Boring Spacers - adapts most boring
bars so crankcases can be bored to fit larger diameter spigots
on big bore cylinders. Enables qualified operator to bore
cases in about an hour after initial setup. Can also be used
to bore pre-1984 style big twin heads when installing big
bore cylinders.
Part 53-0003 - l00ml Buret - used to measure combustion
chamber volume (cc heads) to calculate compression ratio.

●

S&S pinion shafts for Evolution

Sportster

models are the

1987 style splined shaft because this design is stronger than
the later style stock straight shaft and key. As a result, the
engine builder must use a 1986-1987 style pinion gear (H-D

#24055-86 through #24061-86) and oil pump drive gear H-D

#26318-75. Stock Torrington

pinion main bearing in 1986

crankcases must be replaced with 1987 race and later steel
caged roller bearing. See Steps 6 and 10.

●

Due to increased cylinder length, S&S Sidewinder kits of 96"
and larger displacement require that stock cylinder studs be
replaced with big twin cylinder studs.

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.

Read instructions thoroughly before starting work. When they
are completely understood proceed with installation. It is
strongly recommended that the engine builder also obtain a
copy of a Harley-Davidson

service manual of the same year as

the engine being built.

INSTALLATION STEPS:
1.

Clearance Frame*

Crankcase Alignment

Cylinder Mounting Studs (96" and larger engines only)

Bore Crankcases

Modify Crankcases for Oil Returning from Heads

Convert Pinion Main Bearing To 1987 and Later (1986
crankcases only)

Connecting Rod Preparation (79" engines only)

Lower End Assembly

Crankcase and Piston Skirt Clearancing

10. Connecting Rod Alignment*
11. Cylinder Head Preparation
12. Piston to Head and Piston to Valve Clearancing
13. Final Assembly and Engine Installation
14. Engine Break-In Procedure
15. Performance Notes

*NOTE: S&S recommends that engine builder consider
performing some steps during initial engine removal and
disassembly. Checking clearance between stock engine and
frame will allow an accurate estimate of amount and location of
clearancing required after kit is installed. While entire flywheel
and rod assembly may be replaced, it is sometimes helpful to
check original parts combination and note problems that can be
corrected more easily before engine is reassembled.

INSTALLATION

Clearance Frame

NOTE: Piston stability in cylinder bore is improved by using
pistons with the longest possible skirts. In order to provide a
performance engine with the best possible engine life, S&S
increases the cylinder length when the stroke is increased, rather
than decreasing the length of the piston. Frame fit, stock rocker
cover to frame tubes and/or rocker cover to gas tank clearances
in taller than stock engines must be checked and corrected if
needed. It is recommended that frame clearance be measured
before stock engine is removed from frame. The 89" Sidewinder
kit is the largest engine that will fit in a stock frame without
major frame modifications.

To check and clearance frame, perform following steps:
A.

Before stock engine is removed from frame, measure
clearance between rocker boxes and frame. Tightest
spot is normally above and behind rear head.

Kit Part

Displacement

Stroke

Cylinder

Cylinder Length

Number

Length

Compared to Stock

91-3002

79"

⁄

4.650"

Stock Length

91-3204

89"

⁄

5.087"

+.437"

91-3206

91-3304

96"

⁄

5.565"

+.915"

91-3306

91-3504

103"

5.750"

+1.100"

91-3506

Chart 1