Dedicated Subsystem WorkbenchPlatform Gen: 1984–1999
1987 Harley Davidson Evolution 80ci (Dyna / Softail / FXR / Touring) Charging System, Stator AC Output & Battery Health
Stator 3-phase AC voltage at 5,000 RPM, coil resistance, regulated DC voltage, battery code YTX20L-BS (Dyna/Softail) / Y60-N24AL-B (Touring), CCA rating, and multimeter charging diagnostic steps for 1987 Harley Davidson Evolution 80ci (Dyna / Softail / FXR / Touring).
Gen 1984–1999
Factory Platform Compatibility: All workshop fluid capacities, maintenance milestones, torque specifications, and consumables on this specification sheet are factory-identical across model years 1984 through 1999.
Select Model Year:(Active: 1987)
16 Production Years (1984–1999)
Suggested Items3 Verified Workshop Consumables Available for this Job
View Suggested Items ↓3-Phase Charging System & Battery Diagnostic Flowchart
Yuasa & OEM StandardsMultimeter troubleshooting protocols, cold cranking amps (CCA) ratings, 3-phase stator AC outputs, and regulator-rectifier health verification.
OEM Battery Code
YTX20L-BS (Dyna/Softail) / Y60-N24AL-B (Touring) (Heavy-Duty AGM (Reversed Polarity))
Cold Cranking Rating
310 CCA
Capacity (10HR Rate)
18 Ah (12V)
Regulated Output Spec
13.8 - 14.4 V DC at 3,000 RPM
Key-OFF Parasitic Limit
< 1.5 mA
V DC
Multimeter Test Diagnosis
Enter your multimeter terminal reading on the left to view instant diagnostic interpretations and recommended workshop actions.
OEM Factory AGM BatteryOEM Replacement
Yuasa YTX20L-BS Factory Activated Heavy-Duty AGM Battery
Dimensions: 175 L × 87 W × 155 H mm • Weight: 14.2 lbs (6.4 kg). Pre-filled absorbed glass mat technology engineered for heavy vibration resistance.
Lithium LiFePO4 UpgradeUp to 70% Lighter
Antigravity ATX-20-HD Re-Start (680 CCA)
Features built-in RE-START jump starting reserve. Never stranded by dead lights: press the restart button on the top terminal to crank the motorcycle without jumper cables.
Smart Maintainer SpecBattery Life Extension
12V AGM / Float 1.25A
Standard Charge Rate: 1.8A (Max 3.5A). Automated desulfation & float maintenance ensures full capacity retention during off-season winter storage.
Recommended Parts: Yuasa YTX20L-BS Factory Activated Heavy-Duty AGM Battery • Battery Tender Junior 800mA 12V Charger
IGNITION ENGINEERING, HEAT-RANGES & COMBUSTION DIAGNOSTICS
OEM Spark Plugs • Heat-Range Dissipation • Coil Resistance • Visual Combustion Reading Matrix
FACTORY CERTIFIED SPECIFICATIONS
Factory Standard Plug
HD 5R6A
2
Electrode Spark Gap
0.97 - 1.09 mm (0.038 - 0.043 in)
14 mm × 1.25 • 19.0 mm (3/4 in) mm Reach
Hex Drive & Socket Spec
13/16 in (20.8 mm)
Use magnetic rubber-insert thin socket
Tightening Torque (NM)
22 N·m
1/2 turn after gasket contact
Stick Coil Resistances
Pri: 2.5 - 3.5 Ω (Dual Fire Electronic Ignition)
Sec: 10,000 - 12,500 Ω across secondary spark plug towers
Service & Replacement
Inspect: 2,500 mi (4,000 km)
Replace: 5,000 mi (8,000 km)
SPARK PLUG HEAT-RANGE & METALLURGY SELECTOR
Compare OEM standard, fine-wire precious metals, and ambient/duty cycle thermal dissipation paths
Verified Part Specification
HD 5R6A
Metallurgy & Center Tip Architecture
Copper Core / Solid Nickel Alloy Ground Electrode
Thermal Dissipation Path & Physics
Standard OEM factory thermal dissipation rate. Calibrated to stabilize ceramic nose temperature between 500°C–800°C across mixed street, highway, and mountain riding.
Operating Application Envelope
Stock engines, factory ECU mapping, general commuting, and standard touring. Recommended for all baseline maintenance schedules.
Ignitability & Coil Voltage Demand
Standard spark kernel size. Standard secondary coil demand (~15–20 kV). Solid copper core ensures rapid heat conduction away from tip.
SPARK PLUG READING & COMBUSTION DIAGNOSTICS ANALYZER
Interactive visual diagnosis: Match your ceramic insulator tip and electrodes to detect AFR, timing, oil intrusion, and thermal overload
Normal Clean — Optimal Combustion Equilibrium
OPTIMAL COMBUSTIONThermal Operating Range: 500°C – 800°C (932°F – 1,472°F) • Self-Cleaning Pyrolysis Window
Visual Insulator & Electrode Profile
Ceramic insulator nose is light grayish-tan, beige, or light brown. Firing tip and electrodes are dry with minimal combustion deposits. Ground electrode edges remain crisp without rounding or erosion.
Multimeter Electrical Resistance Test
Insulation Resistance > 10 MΩ (Infinite DC resistance between center terminal and steel shell). Dielectric barrier is pristine; zero spark leakage to cylinder head ground.
Probable Root Causes
- Optimal air/fuel ratio across all throttle positions (stoichiometric 14.7:1 cruise, 12.8:1–13.2:1 power enrichment)
- Correct spark plug heat range precisely matched to engine displacement and cooling efficiency
- Ignition timing and coil dwell saturation within factory parameters
- Healthy piston rings and valve guide seals with minimal oil blow-by
Prescribed Workshop Remediation Action
No mechanical intervention required. Inspect gap with wire-style feeler gauge and reinstall to factory torque specification.
Coil-on-Plug (COP) / Stick Coil Multimeter Bench Testing Protocol
Step 1 • Primary Circuit
Set DMM to lowest Ω range. Probe between Terminal 1 (+12V switched) and Terminal 2 (ECU trigger pin). Normal reading: 2.5 - 3.5 Ω (Dual Fire Electronic Ignition) at 20°C.
Step 2 • Secondary Circuit
Set DMM to kΩ range. Probe between Terminal 1 and the high-voltage spark plug spring terminal inside the boot. Factory spec: 10,000 - 12,500 Ω across secondary spark plug towers at 20°C.
Step 3 • Dielectric Boot Inspection
Flex silicone boot under bright light. Check for pinholes, white powdery dielectric breakdown tracks, or hardened silicone causing high-voltage flashover to the cylinder head spark plug tube.
Direct-Fit Ignition Components & Workshop Sockets
Authentic laser iridium plugs, thin-wall magnetic sockets, and OEM replacement stick coils
Harley Davidson Diagnostic Fault Codes & Multimeter Bench Testing
FI & OBD2 DecoderAuthentic factory ECU fault codes, sensor resistance specifications, and harness pinout troubleshooting.
Code P0107Manifold Absolute Pressure (MAP)
MAP sensor input low/open (< 0.20V DC) during key-on or running.
Test: 5.0V VRef at Pin 2; 4.5-5.0V signal key-on engine-off; Pin 1 ground < 0.1V.
Code P0374Crankshaft Position (CKP) Sensor
Zero sync pulses detected from CKP sensor during starter turnover.
Test: Measure 800-1,100 Ω across CKP pins; must generate ≥ 1.0V AC while cranking.
Code P1510Electronic Throttle Control (ETC)
EFI Limited Performance Mode (Limp Mode locked to 20-30% throttle).
Test: Inspect 6-pin throttle body connector for terminal fretting / backprobe TGS 5V sum.
Code B2161Body Control Module (BCM)
Brake Lamp Output open circuit detected when front or rear brake applied.
Test: Test 12V at Blue/Red wire at tail lamp socket; check front brake switch plunger.
Looking for other error codes, sensor pinouts, or OBD2/Euro 5 codes?
Explore Other Subsystems for this 1987 Harley Davidson Evolution 80ci (Dyna / Softail / FXR / Touring)
Jump straight into dedicated factory specifications and interactive workshop diagnostic engines.
Subsystem Guide/torques
Fastener Torques
Engine drain plug, axle spindles, caliper mounts, triple clamp pinch bolts & thread lubrication derating guide.
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Subsystem Guide/fluids
Fluids & Capacities
Oil: 2.84 L (3.00 US qt) • Coolant: N/A • Brake: DOT 5 Silicone-Based (Purple) - strictly NEVER mix DOT 5 with glycol DOT 4
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Subsystem Guide/fuses-relays
Fuses & Relays
Main: 30A Main Thermal Circuit Breaker • Location: N/A
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Subsystem Guide/compression
Compression & Leakdown
Ratio: 8.5:1 • Std: 140-160 PSI • Limit: 120 PSI
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Subsystem Guide/valves
Valve Clearances
Intake: N/A mm • Exhaust: N/A mm
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Subsystem Guide/fuel-delivery
Fuel Delivery & TB Sync
Idle: N/A • Rail Pressure: N/A • Vacuum: N/A
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Subsystem Guide/tires
Tires & Gearing
Front: MT90B16 (Touring) / 100/90-19 (Dyna) / MH90-21 (FXST Softail) • Rear: MT90B16 or 130/90B16
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Subsystem Guide/suspension
Suspension & Sag
Front Travel: 120 mm • Rear Travel: 76 mm
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Subsystem Guide/maintenance
Maintenance Schedule
Oil: Every 2,500 - 5,000 mi (4,000 - 8,000 km) mi • Valves: N/A • Plugs: Every 5,000 mi (8,000 km) mi
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