S&S Cycle IST Ignition System for 1984–99 4 1/8 Bore Big Twin Engines User Manual

Page 7

Hold knock sensor in position by hand only while torquing. Do NOT use pliers. Damage to knock sensor will occur.

3. Installation of the MAP Sensor

a. Replace the existing VOES vacuum hose with the one provided. Trim the hose to a length that will locate the MAP Sensor so it does not

interfere with the engine Temperature or Knock sensors, or motor mount hardware. A hose length in the 1 to 2 inch range is acceptable.
If the vacuum fitting in the intake manifold is used for other equipment, the line may be cut near the manifold, and the supplied tee may
be used. The total line length from the manifold to the sensor should be kept less than 9 inches—shorter if practical.

b. Remove the orange rubber seal at the end of the MAP Sensor with a pair of needle nose pliers.

c. Attach the MAP Sensor to the hose. It is recommended to use wire ties around vacuum hose connections.

4. Installation of the Ignition Coil

a. A single-fire coil may be installed in the location where the dual-fire coil was. It should have front and rear connections which go to the

module and front and rear spark plug wire connections. Other single fire coils may be used by modifying the supplied harness.

b. Do not use the motorcycle’s existing coil harness—a coil harness is provided.

c. Primary coil resistance should be in the range of 0.5 to 3 ohms.

5. Installation of the Crank Position Sensor

a Remove the screw(s), cover plate, and gasket from the front of the engine crankcase near the oil filter. See Picture 10, below.

b. Install the Crank Position Sensor with the supplied 1/4" bolt and lockwasher and torque to 8-10 ft-lb.

6. Installation of the IST Ignition Module and 41/8" Bore Wiring Harness Adapter:

The 41⁄8" Bore Engine Wiring Harness Adapter (See Picture 11, next page) is a one-piece assembly consisting of the following connectors:

(a) IST Ignition Module Connector: 32-Socket, Gray (Delphi®/Packard)—Connects to the S&S® Intelligent Spark Technology Ignition Module.

(b) Motorcycle Main Harness Connector: 8-socket Black (Deutsch)—Connects to the stock Harley-Davidson® wiring harness in place of the

stock module.

(d) Knock Sensor Connector: 2-Socket black (Bosch)

(e) MAP Sensor Connector: 3-Socket (Delphi®/Packard)

(f) Coil Harness Connector: 3-Socket black (Delphi®/Packard)

(g) Crank Position Sensor Connector: 2-Socket black (Deutsch)

(h) Data Link Connector with Plug: 4-Pin gray (Deutsch)

The IST ignition module includes a hardware packet. The hardware is intended for spacing the module and the connector off of the

mounting back plate. Washers are also included for the mounting screws. This hardware is only necessary on some models. The hardware
packet includes the following spacers and washers:

Picture 10

CAUTION