2021 Harley-Davidson FLHR Road King — Maintenance & Ownership Guide
Routine Maintenance
Key maintenance tasks to keep your 2021 Harley-Davidson FLHR Road King running reliably.
Oil Service
Requires a '3-hole' oil change: Engine (~5.2 qts), Primary (~1.1 qts), and Transmission (~1.0 qt).
Clutch Adjustment
The 2021 return to a cable clutch requires periodic free-play adjustment at the lever and cable adjuster.
Common Wear Items
Parts that wear over time on the 2021 Harley-Davidson FLHR Road King and should be inspected regularly.
Tires
Heavy touring chassis often causes the rear tire (Dunlop D407T) to flat-center and the front (D408F) to cup if pressures are not maintained.
Brake Pads
Brembo pads provide excellent stopping power but can wear quickly under heavy touring use or aggressive braking.
Popular Upgrades
The most popular aftermarket upgrades for the 2021 Harley-Davidson FLHR Road King.
Stage 1 Performance
Commonly upgraded with slip-on mufflers, a high-flow air intake, and a tuner to reduce engine heat and improve sound.
Handlebars
Many riders find the stock 'buckhorn' style bars uncomfortable for long distances and swap them for 10-14 inch ape hangers.
Common Replacement Parts
Parts that commonly need replacing on the 2021 Harley-Davidson FLHR Road King.
Clutch Cable Adjuster
The OEM plastic cable adjuster is prone to cracking or failing, often replaced with an aftermarket metal version.
Battery
The 405 CCA battery is high-output but sensitive to parasitic draw; requires a tender during storage to prevent premature failure.
Used Buying Inspection Checklist
What to look for when buying a used 2021 Harley-Davidson FLHR Road King.
Left Switch Pack
Check if the bike starts in gear with the clutch pulled; failures in the clutch safety switch are common in early M8 models.
Clutch Cable Adjuster
Inspect the plastic adjuster housing for cracks or signs of being forced, as this is a known weak point on 2021+ models.
Neck Bearings
Check for 'notchiness' or excessive play in the steering head, which can lead to low-speed wobbles.
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