Dedicated Subsystem WorkbenchPlatform Gen: 2020–2024

2020 Harley Davidson Low Rider S (FXLRS Milwaukee-Eight) Throttle Body Synchronization & Fuel Delivery

Multi-cylinder vacuum sync specs, idle speed, EFI high-pressure fuel rail PSI, and injector resistance multimeter bench for 2020 Harley Davidson Low Rider S (FXLRS Milwaukee-Eight).

Gen 2020–2024

Factory Platform Compatibility: All workshop fluid capacities, maintenance milestones, torque specifications, and consumables on this specification sheet are factory-identical across model years 2020 through 2024.

Select Model Year:(Active: 2020)

2020 2021 2022 2023 2024

Engine

1868cc

Drive

Chain

Cooling

Air/Oil-Cooled

FSM Induction Calibration45° V-Twin (Milwaukee-Eight) (2 Throttle Bores)

Fuel Delivery, Throttle Body Synchronization & Manometer Balancer

Factory intake depression specifications (260 mmHg), electronic fuel pump pressure testing (58 PSI), injector resistance, and interactive multi-column manometer balancing.

Warm Idle: 850 - 950 RPM

Quick Workshop Diagnostic Presets

Simulate Throttle Linkage Asymmetry, Hunting Idle, or Intake Boot Vacuum Leaks

OPTIMAL SYNCHRONIZATION: BALANCED (Δ ≤ 15 mmHg)

Diagnostics:Max Differential: Δ 0 mmHg (Factory Max Tolerance: ≤ 15 mmHg)

All 2 throttle plates pull uniform intake depression within factory engineering tolerance (≤ 15 mmHg / 2.00 kPa). Delivers immediate linear throttle pickup, silky smooth idle, uniform cylinder torque pulses, and balanced exhaust temperatures.

Workshop Multi-Column Fluid Manometer

Damped intake depression columns. Target spec: 260 mmHg (±15 mmHg) at warm idle (850 - 950 RPM).

Reference: Single 55mm Electronic Throttle Body (Dual Cylinder Common Plenum)

Mechanism: Bypass Screws

CYL #1

MASTER REF

260mmHg

34.7 kPa · 10.2 inHg

±0 mmHg (Exact Target)

Fixed Reference Master. Synchronize all slave throttle bodies to match this column.

CYL #2

SLAVE BORE

260mmHg

34.7 kPa · 10.2 inHg

±0 mmHg (Exact Target)

Vacuum Take-Off Ports: Rubber plug capped vacuum test port on intake manifold branch

Damping Protocol: Restrictor valves must be adjusted until columns oscillate no more than ±5 mmHg per intake stroke.

Fuel Pump Pressure & 5-Min Hold Test

EFI Pressure Rail

Running Fuel Pressure

58 PSI(4.00 bar)

OEM Running Spec

58 PSI (±3 PSI)

PASS: WITHIN OEM RUNNING SPEC

Fuel pump delivery pressure is 58 PSI (Factory spec: 58 PSI ± 3 PSI / 4 bar). High-pressure regulator and pump rotor operating within factory design threshold.

Connect mechanical gauge to the quick-disconnect fuel rail fitting using an OEM banjo or T-adapter.

Fuel Injector Resistance & Induction Specs

Multimeter Bench Check

OEM Injector Solenoid Resistance

12.5 - 13.5 Ω at 20°C

Measure across injector 2-pin harness socket with ignition OFF. Internal coil resistance increases by ~0.4% per °C rise above 20°C (68°F). Replace injector if resistance reads open (> 100 kΩ) or shorted (< 2 Ω).

Bore Diameter

55 mm

Operating Temp

80°C (176°F)

Induction Type

Sequential Port Fuel Injection (ESPFI) with 55mm Electronic Throttle Body

Injector O-rings must be lubricated with a light coat of clean engine oil before seating into fuel rail.

4-Step Throttle Body Synchronization Protocol

Official workshop manual step-by-step checklist. Mark each step as you complete it on the workbench.

0 of 4 Steps Complete

1CLICK TO MARK DONE

Engine Pre-Flight Conditioning

Check and adjust valve clearances to spec before attempting sync. Ensure air filter is clean, spark plugs are fresh, and engine is fully warmed to operating temperature (80°C–90°C).

2CLICK TO MARK DONE

Manometer Connection & Damping

Connect 2-column liquid or digital manometer hoses to Rubber plug capped vacuum test port on intake manifold branch. Adjust in-line hose restrictor valves to dampen rapid intake pulsation until fluid columns stabilize.

3CLICK TO MARK DONE

Balance Screw Calibration

With engine idling at 850 - 950 RPM, identify Single 55mm Electronic Throttle Body (Dual Cylinder Common Plenum). Adjust Common throttle bore with Electronic Throttle Control (ETC) and manifold air pressure balance until all cylinder columns are within 15 mmHg (2.00 kPa) of the master reference.

4CLICK TO MARK DONE

Throttle Blip & Locknut Verification

Blip throttle to 3,000 RPM 2–3 times and verify columns return evenly to idle balance. Tighten any balance screw locknuts securely, re-install rubber vacuum sealing caps, and verify idle speed.

Shop Carb & Throttle Body Cleaners→Shop Multi-Column Manometers & Sync Tools→Shop EFI Fuel Pressure Test Gauge Kits→

Official NHTSA Safety Recalls & Technical Bulletins

0 Open Campaigns (Clean)

U.S. Department of Transportation compliance database (Title 49 U.S.C. Chapter 301).

Verify VIN on NHTSA.gov

No Active Federal Safety Recalls Reported

The U.S. DOT National Highway Traffic Safety Administration (NHTSA) records zero open safety recall campaigns for the 2020 Harley Davidson Low Rider S (FXLRS Milwaukee-Eight) platform. Always check your individual 17-digit VIN at an authorized dealership or via NHTSA.gov for individual recall completions.