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INTRODUCTION

Installation of an S&S

Harley-Davidson

Sportster

model 3

⁄8"

bore stroker Sidewinder

Kit is easy and can be performed by

any Harley-Davidson

repair shop equipped to do complete

ngine overhauls.

OTES:

● To make installation of S&S Sidewinder series 3

⁄8" bore kits

easier, S&S has designed several Special Tools worth

considering. They are:

Part 53-0002 - Connecting Rod Checking Pin - helps check

iston 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 pr

oducts are original equipment parts or that they

e equivalent to the corr

esponding Harley-Davidson

par

number shown.

Read instructions thoroughly before starting work. When they

are completely understood proceed with installation. It is

strongly r

ecommended that the engine builder also obtain a

copy of a Harley-Davidson

ser

vice manual of the same year as

the engine being built.

INSTALLATION STEPS:

1. Clearance Frame*

2. Crankcase Alignment

. Cylinder Mounting Studs (96" and larger engines only)

. Bore Crankcases

5. Modify Crankcases for Oil Returning from Heads

6. Convert Pinion Main Bearing To 1987 and Later (1986

crankcases only)

. Connecting Rod Preparation (79" engines only)

8. Lower End Assembly

9. Crankcase and Piston Skirt Clearancing

10. Connecting Rod Alignment*

1. 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

1. 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 r

ocker boxes and frame. Tightest

spot is nor

mally above and behind r

ear head.

Kit Par

Displacement Stroke

Cylinder

Cylinder Length

Number

Length Compar

ed to Stock

91-3002 79"

⁄16"

4.650"

Stock Length

91-3204

89" 4-

⁄16" 5.087" +.437"

91-3206

91-3304

96"

⁄8"

5.565"

+.915"

91-3306

91-3504

103" 5" 5.750" +1.100"

91-3506

Chart 1