How Did The Milwaukee-eight Engine Get Its Name?

Harley-Davidson introduced nan Milwaukee-Eight for nan 2017 exemplary year, making it nan ninth procreation of nan bikemaker's signature "Big Twin" engines. It succeeded nan Harley Twin Cam motor, which had been successful accumulation since 1998 and was getting a spot agelong successful nan tooth. The Milwaukee-Eight's engineering and creation instruction was driven by nan looming reality of stringent world emissions standards, on pinch nan request to springiness Harley loyalists nan capacity they were longing for.

The sanction Milwaukee-Eight is pure, unadulterated trading spiel. "Milwaukee" denotes nan location of Harley-Davidson's firm office successful Wisconsin, while nan number "Eight" denotes nan number of valves successful nan engine. That's 4 valves per cylinder, a monolithic departure from nan accepted two-valve pushrod motor architecture that defined Harley-Davidson motors.

Mechanically, nan Milwaukee-Eight retains nan classical 45-degree V-twin Harley motor format. However, nan valvetrain has been wholly redesigned. While nan outgoing Twin Cam utilized dual camshafts, nan Milwaukee-Eight reverted to a single, chain-driven camshaft, arsenic a single-cam layout reduces mechanical clatter and friction. The camshaft operated 4 valves via a strategy of forked rocker arms. 

Harley initially launched nan Milwaukee-Eight pinch 2 displacements -– a modular 107-cubic-inch (1750cc) and a monolithic 114-cubic-inch (1868cc) type reserved for its range-topping Custom Vehicle Operations (CVO) models which are a acold outcry from Harley Davidson's astir affordable bikes. In 2019, nan bikemaker came up pinch nan larger Milwaukee-Eight 117 (1902cc), and successful 2023, an moreover larger Milwaukee-Eight 121 (1,977cc) VVT that featured adaptable valve timing. Harley besides offers a Screamin' Eagle 135 cubic inch (2,212cc) capacity crate engine.

The Milwaukee-Eight is arguably Harley-Davidson's astir precocious air-cooled engine, acknowledgment to its importantly improved volumetric ratio and effective thermal guidance strategies. The move to a four-valve cylinder caput accrued intake and exhaust valve aerial travel by a whopping 50% complete nan erstwhile Twin Cam engine. This monolithic summation successful travel capacity allowed nan dense cruiser motor to respire much efficiently.

To guarantee complete combustion crossed nan monolithic bore of nan elephantine copy cylinders, nan Milwaukee-Eight motor besides has a dual-ignition strategy acknowledgment to 2 spark plugs per cylinder. The resultant dual occurrence fronts guarantee a faster and much complete air-fuel substance burn, which helps trim emissions and besides actively prevents pre-detonation aliases motor knock.

Cooling was a captious engineering attraction during nan improvement of nan Milwaukee-Eight, truthful nan motor uses targeted cooling successful nan cylinder heads, specifically focusing connected nan metallic bridges astir nan exhaust valves, wherever temperatures tin get beautiful high. Depending connected nan engine, you either sewage "precision lipid cooling," which routed lipid done passages successful nan cylinder heads, aliases "twin-cooling," which routed liquid coolant done nan cylinder heads from a mini radiator hidden successful nan little portion of nan fairing.

This attack to cooling allowed engineers to support a higher compression ratio of up to 10.5:1 without worrying astir cooking nan rider's legs. The centrifugal besides featured an upgraded charging strategy that delivered 50% much complaint astatine idle than its Twin Cam predecessor. This was done specifically to support modern physics accessories for illustration monolithic GPS screens and heated seats.

Harley-Davidson's modern V-twin motor has been astir for a while, and while it is hailed for its capacity and NVH levels, the Milwaukee-Eight still has immoderate drawbacks. Let's commencement pinch nan positives, of which nan astir important is its precocious volumetric efficiency. The four-valve per cylinder layout offers amended breathability, which successful move helps it connection higher powerfulness output and moreover an 11% betterment successful 0-60 mph acceleration times complete its predecessor.

The motor features an betterment successful vibration guidance arsenic well. It has an soul counterbalancer that cancels retired 75% of superior motor vibrations astatine idle. This helps forestall nan motor from shaking itself isolated while retaining the bully vibrations that Harley riders adore. The centrifugal besides gets sound sensors integrated connected nan motor cylinders, which helps nan ECU to set spark timing dynamically based connected nan substance quality. Then you person nan precision cylinder caput cooling that prevents basking spots and allows nan motor to tally astatine a much accordant temperature, and improves longevity.

The negatives commencement pinch nan valvetrain complexity. The move to 4 valves per cylinder increases nan number of moving parts successful nan cylinder head. This intends added complexity, compared to nan older engines that made old-school top-end rebuild successful your car shed a elemental affair.

Early Milwaukee-Eight engines (2017 to 2019) were notorious for a mechanical flaw known arsenic "oil sumping. It had a flawed lipid pump creation that caused lipid to accumulate successful nan crankcase alternatively than return into nan tank. This caused monolithic resistance connected nan flywheel, causing nan centrifugal to suffer powerfulness astatine precocious speeds. The early Milwaukee-Eight engines besides had lipid transportation issues, wherever transmission fluid would leak into nan superior case.