Used parts for the 2017-present Harley-Davidson FLHT Electra Glide family with the Milwaukee-Eight 107 engine (1746cc) are stocked at Sun Coast Cycle Sports. The M8 107 replaced the Twin Cam 103 across Harley's entire Touring lineup for 2017, delivering four-valve cylinder heads, a single camshaft, and dual counterbalancers. This page covers all FL dresser variants: the FLHT Standard, FLHTC Classic (through 2018), FLHTCU Ultra Classic, and the FLHTK Ultra Limited with Twin-Cooled or fully liquid-cooled heads. Technicians at our Florida facility pull each component from donor Electra Glides, photograph it with a unique SKU, and ship free within the continental U.S.
FLHT Electra Glide 107ci generation and parts compatibility
The Milwaukee-Eight 107 Electra Glide era began in 2017 and represents a complete engine and suspension overhaul from the Twin Cam 103 it replaced. No TC103 engine components interchange with the M8 107. However, the Touring chassis carried over from the 2014 Rushmore platform, so many frame, bodywork, and accessory components share compatibility across the TC103 Rushmore and M8 eras.
| Years | Engine Options | Suspension | Key Notes |
|---|
| 2017-2019 | M8 107 (oil-cooled) or Twin-Cooled M8 107 (FLHTK) | Showa SDBV fork, emulsion rear shocks | New engine, new suspension, Boom! Box carries over |
| 2020+ | M8 114 (1868cc) standard on most models | Continues Showa SDBV | Many models bumped to 114ci; verify displacement before ordering engine parts |
The 2017 M8 introduction changed the engine, primary drive, exhaust, and air cleaner completely. The M8 107 uses four valves per cylinder (vs two on TC103), a single camshaft (vs twin cams), dual spark plugs per cylinder, and an internal counterbalancer. These architectural differences mean no internal engine components cross over from the TC103. The 6-speed transmission was also revised with new gear ratios optimized for the M8's torque characteristics.
Chassis-level compatibility with 2014-2016 Rushmore models is partial. The frame dimensions carried forward, so saddlebags, Tour-Pak, seats, and some bodywork from 2014-2016 TC103 Rushmore models may physically fit 2017+ M8 bikes. However, exhaust routing changed, the engine profile is different, and electrical connectors were updated, so verify specific part compatibility before ordering. The Boom! Box infotainment system carried over from the Rushmore era with software updates.
For 2020+, Harley bumped most Touring models to the M8 114 (1868cc) as standard equipment. If you are sourcing engine-specific parts for a 107ci Electra Glide, confirm the actual engine displacement on the donor bike. The M8 107 and 114 share the same crankcase architecture, so many external components interchange, but cylinders, pistons, and the crankshaft stroke differ between the two displacements.
Common FLHT Electra Glide 107ci failure points and replacement parts
Oil cooler and oil sumping at idle: The M8 107's oil management system directs oil through channels in the cylinder heads for cooling. Some owners report oil sumping (pooling in the crankcase at idle), which can cause a brief oil pressure light on startup. This is a design characteristic rather than a defect, but extended idle periods can exacerbate it. Riding the bike regularly and avoiding prolonged idling minimizes the issue.
Exhaust header gasket leaks: The M8 exhaust header-to-cylinder connection can develop gasket leaks, presenting as a ticking noise that varies with engine temperature. The header gaskets on the M8 use a different design than the TC103 and are not interchangeable. Replacement with OEM or high-quality aftermarket gaskets resolves the noise.
Boom! Box infotainment glitches: The Boom! Box system continues from the TC103 Rushmore era with similar touchscreen, Bluetooth, and GPS issues. The 2017+ models received updated software, but persistent problems may require head unit replacement.
Twin-Cooled coolant system maintenance (FLHTK): The Twin-Cooled M8 107 on Ultra Limited models requires coolant level monitoring and periodic flush per the maintenance schedule. Coolant leaks at hose connections and the water pump gasket have been reported at higher mileage.
Primary chain tensioner shoe wear: The M8 uses an automatic primary chain tensioner with a nylon shoe that wears over time. At high mileage (40,000+ miles), the shoe can thin enough to allow chain slack, producing noise and inconsistent clutch engagement during acceleration.
Commonly replaced FLHT Electra Glide 107ci parts
- Exhaust header gaskets and exhaust system
- Primary chain tensioner shoe
- Boom! Box infotainment head unit
- Tour-Pak trunk, latches, and hinges (FLHTCU/FLHTK)
- Batwing fairing outer shell and inner panel
- Twin-Cooled coolant hoses and water pump gasket (FLHTK)
- Stator and voltage regulator
- Brake pads and rotors
Frequently asked questions
Q: Will Twin Cam 103 Rushmore parts fit my Milwaukee-Eight 107 Electra Glide?
It depends on the component. The M8 Touring frame dimensions carried over from the 2014 Rushmore platform, so saddlebags, Tour-Pak, seats, floorboards, and many trim pieces from 2014-2016 TC103 models may physically fit. Engine, exhaust, air cleaner, and primary drive components are completely incompatible between TC103 and M8. Electrical connectors were also updated, so verify wiring compatibility on any electronic accessories.
Q: Can I install M8 114 cylinders and pistons on my M8 107 engine?
Yes. The M8 107 and 114 share the same crankcase architecture. The displacement difference comes from a larger bore on the 114 (4.016" vs 3.937") with the same stroke. You can install M8 114 cylinders and pistons onto the M8 107 cases. An ECM tune is required to match the increased displacement. Harley also offers Screamin' Eagle Stage kits that take the M8 to 128ci or 131ci using the same cases.
Q: What distinguishes the oil-cooled M8 107 from the Twin-Cooled version?
Both are 1746cc Milwaukee-Eight 107 engines with identical bore, stroke, and crankcase. The oil-cooled version (FLHT, FLHTC, FLHTCU, Road King, Street Glide, Road Glide) routes engine oil through passages in the cylinder heads for cooling. The Twin-Cooled version (FLHTK Ultra Limited, Road Glide Ultra, Tri Glide Ultra) adds liquid-cooled cylinder heads with water passages, radiators in the fairing lowers, and an electric water pump. Twin-Cooled heads have a higher compression ratio and produce slightly more power. The two head types are not interchangeable without converting the entire cooling system.
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