Harley-Davidson Shovelhead and Evolution Big Twins Repair Manual 1970-1999
The 1970-1999 Harley-Davidson Shovelhead and Evolution Big Twins repair manual by Haynes covers Harley FL, FX, FLT, FLH, FXR, Dyna, and Softail (1200cc and 1340cc) models.
Note: this repair manual DOES NOT include Police editions.
Book Excerpt: 1970-1999 Harley-Davidson Shovelhead and Evolution Big Twins Repair Manual
GENERAL INFORMATION
In order for the engine to run correctly, an electrical spark must ignite the fuel/air mixture in the combustion chambers at exactly the right moment in relation to engine speed and load.
The ignition system operation is based on feeding low tension (primary) voltage from the battery to the coil where it's converted to high tension (secondary) voltage by a process known as induction.
The secondary voltage is powerful enough to jump the spark plug gap in the cylinders many times a second under high compression pressures, provided the system is in good condition and all adjustments are correct.
The ignition system installed on 1970 through early 1978 models as standard equipment is a mechanical contact breaker point type. The points are contained in a cone-shaped housing on the right side of the engine.
The system installed on late 1978 and later models is a breakerless inductive discharge system (electronic ignition).
Both systems are divided into two circuits: the primary (low tension) circuit and the secondary (high tension) circuit.
The primary circuit consists of the battery, the contact breaker points (early models), the ignition timer (late 1978 and 1979) or the computerized ignition timer (1980-on), the primary coil the ignition switch and the wires connecting the components.
STARTER DRIVE: DISASSEMBLY, INSPECTION AND REASSEMBLY
The starter motor utilizes a reduction gear to drive the gear mounted on the clutch outer drum. On all models through 1988, the reduction driven gear turns a shaft on which a free-sliding pinion gear is mounted.
When the starter button is operated, the starter solenoid moves the pinion gear into mesh with the clutch outer drum gear a moment before power is provided to the starter motor. The starter solenoid operates a pivot arm, which operates the pinion gear.
On 1989 and later models, the pinion shaft is replaced by the jackshaft. A gear on the left end of the jackshaft is always engaged with the gear on the clutch outer drum and the starter drive connects and disconnects the motor from the jackshaft.
TABLE of CONTENTS:
LIVING WITH YOUR HARLEY-DAVIDSON BIG TWIN
Introduction: Miwaukee magic | Ackowledgements | About this manual | Identification numbers: buying spare parts; decoding the Vehile Identification Number (VIN) | Safety first!
