- Harley-Davidson Engines
Revolution Max 1250
With this engine, Harley-Davidson is opening a new chapter in the legendary V-twins. It serves as a co-supporting chassis element that makes a conventional frame superfluous. This significantly reduces the overall weight of the machine, keeping the center of gravity low and optimizing handling. It offers massive power (152 hp), ample torque (128 Nm) and an extremely wide usable rpm range.
The liquid-cooled V2 has a 60° cylinder angle, with the connecting rods offset by 30 degrees on the crankshaft.
Two overhead camshafts per cylinder (DOHC) provide high peak power, while variable valve timing (VVT) ensures plenty of torque and a wide usable rpm range.
All this adds up to excellent acceleration from a standstill and decent power at high rpm. The sound is described as pleasant and two balancer shafts ensure smooth running with little vibration – perfect for long tours on and off paved roads!
Oil circulation system
The Harley-Davidson Milwauke-eight engine has been installed in all Touring models since model year 2017 and in new Softail vehicles since 2018. After almost 20 years, the engine replaces the Twin Cam engine, from which it differs markedly through its four-valve technology and better response from the speed cell. The engine’s sound is even more pleasant and uses less fuel, with an unprecedented yet typical Harley-Davidson feel.
The four-valve cylinder heads per cylinder allow an increased gas flow rate of 50% more than the previous two-valve heads. Combined with more efficient combustion due to the new dual ignition, the Milwaukee Eight achieves up to 10% more torque with 11% less fuel consumption. With just one chain-driven camshaft, the Milwaukee Eight’s valve drive is lighter, quieter and simpler than the Twin Cam engine. 75% of the first order vibrations are balanced by a spur gear internal balancer shaft for increased driving comfort. The classic character of a gently shaking Harley V2 is fully retained. At high speeds, the rubber mount ensures smooth vibration behaviour. Current versions are available in 107, 114 and 117 cubic inches. The new engine is below the worldwide noise limits, while the rich exhaust sound is better than ever before. The four-valve cylinder heads per cylinder enable an increased gas flow rate of 50% more than the previous two-valve heads.
For the typical ignition sequence of a Harley-Davidson Big Twins the Milwaukee-Eight was again given a cylinder angle of 45 degrees and both conrods run on the same crankpin. The interaction provides the famous “Potato, Potato” sound. The idle speed of the Milwaukee Eight was lowered from 1,000 to 850 rpm to make the Harley run quieter and quieter when stationary. The Milwaukee Eight engine has a further developed charging system that delivers 50% more power at 26 amps in idle speed in order to supply the growing proportion of technical gadgets with power in a future-oriented manner.
|Bore x Stroke
|100,0 x 111,1 mm
|102,0 x 114,3 mm
|103,5 x 114,3
|Power kW (PS)/U/min
Thunderbike Custombikes with Milwaukee-Eight
Harley-Davidson Engine History
1999 – 2016 Twin Cam
The Twin Cam engine delivered more torque and power than the Evolution model and was originally available as a carburetor or with fuel injection. Problems with oil circulation in the Evolution engine prompted Harley-Davidson to equip the Twin Cam with a more powerful internal twin engine oil pump. Meanwhile, the engine reaches up to 1801ccm³ and up to 97 hp.
1984 – 1999 Evolution
The 1340ccm³ Evolution engine lived up to its name because it was a true evolution. The “Evo” needs significantly less fuel and generates significantly more torque at the same time. On top, it turns more quietly and is therefore also more durable. It was the engine for the then brand-new Softail, which today is regarded as the forefather of the complete Softail series. Depending on the version, it achieves up to 65 hp.
1957 – 1984 Ironhead
The then new small, modern engine with a sporty character is driven by a spur gear camshaft. The version with cast iron cylinder and cylinder heads still had 883cm³, this is why it is called Ironhead. The engine was used to drive the then new Sportster series. It was the first Harley that had a whole horsepower per cubic inch.
1948 – 1965 Panhead
The Panhead engine, which had 60 hp at its deceleration in 1965, was a model for the Electra Glide and already had an electric starter at that time. The Panhead takes its name from the unmistakable cake pan look of the rocker boxes. New aluminium cylinder heads, hydraulic valve lash adjustment and optimised lubrication and cooling make the 1200 Panhead stronger, lighter and more durable.
1929 – 1973 Flathead
Named after its flat curved cylinder heads, the first Flathead engine appeared in 1929. The valves were arranged sideways. The Flathead engine is optimized up to 1340cm³ capacity and 34 HP. Until 1952 it was used in motorcycles and even until 1973 in the three-wheeled Servi Cars.
The two-cylinder engine with a 45° cylinder angle is designed by Harley-Davidson to achieve more power than the current single-cylinders. The 810cm³ and 7 PS strong V-Twin engines are only produced in a small series of 27 pieces.