Boost Milwaukee-Eight Performance with New Harley Screamin’ Eagle Stage Kits

Harley Screamin' Eagle Street Cannon Exhaust in black

Harley Screamin’ Eagle Street Cannon Exhaust in black

The potent performance of the new Harley-Davidson Milwaukee-Eight engine is amplified by new Screamin’ Eagle Performance Products available now from Harley-Davidson Genuine Motor Parts & Accessories. Building performance with precision, Screamin’ Eagle for Milwaukee-Eight ramps up horsepower, torque and throttle response without compromising the refined riding experience delivered by the new Big Twin engine in 2017 Harley-Davidson Touring models.

“Harley-Davidson Genuine Motor Parts & Accessories has a key advantage over the aftermarket – unmatched knowledge of the Milwaukee-Eight and the ability to engineer performance upgrades during the development of the engine,” said Scott Habegger Director of Portfolio Management. “Screamin’ Eagle Performance Products are not an after-thought or an add-on for Milwaukee-Eight. These kits were engineered alongside the engine for factory-level quality and fit, which is why only Harley-Davidson dealers can offer 50-state, U.S. EPA compliant Screamin’ Eagle performance parts backed by a factory warranty.”

Screamin’ Eagle Stage I, Stage II and Stage III upgrades for Milwaukee-Eight engines offer escalating performance benefits with components that have been engineered by Harley-Davidson to work together to boost output with no compromise in reliability or rideability.

Screamin’ Eagle Stage I for Milwaukee-Eight = Intake + Exhaust + Tuning Upgrade
Stage I is the foundation for further Milwaukee-Eight performance upgrades. High-performance air cleaners and slip-on mufflers flow more air into and out of the engine and produce a 5 to 10 percent average increase in power that riders can feel throughout the entire RPM range. Ideal for riders that want to enhance the performance, look and sound of their motorcycle, Stage I upgrades can be completed without engine disassembly, and no special tools are required.

Screamin' Eagle Ventilator Air Cleaner for Milwaukee-Eight engine

Screamin’ Eagle Ventilator Air Cleaner for Milwaukee-Eight engines

Screamin’ Eagle Air Cleaners for Milwaukee-Eight
Three Screamin’ Eagle performance air cleaner choices for Milwaukee-Eight include a K&N oiled cotton filter element that is washable and reusable.

• The Screamin’ Eagle High-Flow Air Cleaner (P/N 29400246 Chrome $184.95*, P/N 29400245 Black, $174.95*) filter element hides behind the stock air cleaner cover for a subtle look. The back-plate permits flow around the entire perimeter of the air cleaner and through the ram air opening at the front of the air cleaner cover for maximum airflow.

• The Screamin’ Eagle Ventilator Air Cleaner (P/N 29400298 Gloss Black, P/N 29400299 Chrome; $299.95*) offers a tapered, low-profile design for enhanced rider leg room. The exposed filter element and a cast back plate are designed to provide maximum air flow to the throttle body. A water repellent rain sock (sold separately) protects the oiled cotton filter element during stormy rides

• The Screamin’ Eagle Heavy Breather Performance Air Cleaner (P/N 29400263 Chrome, P/N 29400264 Gloss Black; $399.95*) features a low-profile cast aluminum tube that directs air into the throttle body with minimal turbulence for increased efficiency. A new slanted, compact filter shape allows installation on bikes with fairing lowers. The back-plate has integral breathers and covers the throttle body and electronics for a show-quality presentation. A water-repellent rain sock is included.

Harley Screamin' Eagle Heavy Breather Intake for Milwaukee-Eight engines

Harley Screamin’ Eagle Heavy Breather Intake for Milwaukee-Eight engines

Screamin’ Eagle Street Cannon Performance Slip-on Mufflers (P/N 64900552 Chrome, P/N 64900553 Satin Black; $499.95*) designed specifically for the Milwaukee-Eight engine enhance airflow and power by reducing exhaust gas back-pressure and enhancing the effects of wave and inertia scavenging. These 4.5-inch-diameter mufflers have a unique baffle design to produce a richer, deeper tone at idle, part throttle and when accelerating, yet comply with emissions and sound regulations. The muffler end caps are sold separately so customers can choose the style and color they prefer.

Optimized engine performance with Stage I intake and exhaust system must be accompanied by a new Electronic Control Module (ECM) calibration that tunes the EFI for the new components. The new Screamin’ Eagle Pro Street Tuner (P/N 41000008C, $299.95*) is designed to simplify ECM calibration as performance modifications are made. Unlike many aftermarket tuners, the Screamin’ Eagle Pro Street Tuner re-programs the motorcycle’s operating system; it isn’t a piggyback system that tries to fool the ECM into adding more fuel or changing the ignition timing. The Pro Street Tuner plugs into the bike’s data port, so no splicing or under-seat hardware is required. The Pro Street Tuner can be used to upload the latest Engine Control Module (ECM) calibrations to match a bike’s state-of-tune. Ideal for real-world street performance applications, the Pro Street Tuner provides adjustability to accommodate bike-to-bike variation and for changes to cams, heads, intake and exhaust while maintaining closed-loop fuel control for optimal fuel economy in the part-throttle operating range. All current street-compliant ECM calibrations are included in the software with unlimited access to future calibrations and free software updates downloadable via the user website. The Pro Street Tuner stores up to 15 minutes of run-time data that can be downloaded to a PC and viewed and evaluate the bike’s air/fuel ratio, oxygen sensor readings, engine speed and temperature, RPM and vehicle speed, throttle position, spark advance and much more. Diagnostic Trouble Codes can also be viewed and deleted. Unlike other race tuners or engine controllers, the Screamin’ Eagle Pro Street Tuner is 50-state EPA compliant and does not impact the Harley-Davidson factory warranty coverage.

Harley Screamin' Eagle Pro Street Tuner for Milwaukee-Eight engines

Harley Screamin’ Eagle Pro Street Tuner for Milwaukee-Eight engines

Screamin’ Eagle Stage II for Milwaukee-Eight = Stage I + Performance Camshaft
Take a Screamin’ Eagle Stage I equipped Harley-Davidson Milwaukee-Eight engine to the next level with a Screamin’ Eagle Milwaukee-Eight Stage II Kit. Each kit features a performance camshaft that increases air flow by lifting the cylinder head valves higher and holding them open for a longer period of time than the stock cam, which enables greater intake and exhaust flow. Harley-Davidson Genuine Motor Parts & Accessories offers two Screamin’ Eagle Stage II camshaft choices for the Milwaukee-Eight engine to allow riders to focus performance based on riding style. ECM calibration with Screamin’ Eagle Pro Street Tuner is required for proper installation.

• The Screamin’ Eagle Milwaukee-Eight Stage II – Torque Kit (P/N 92500047, $389.95*) delivers on-demand throttle response from low to mid RPM at cruising speed. Installed in the Milwaukee-Eight, this cam produces more than 100 lb-ft of rear wheel torque from 2,500 to 4,500 RPM in Milwaukee-Eight 107 engines, an ideal power band for passing slow-moving vehicles without a downshift and compensating for the weight of a passenger and luggage. Kit components include a Screamin’ Eagle SE8-447 cam, adjustable pushrods, pushrod covers, O-rings, and a cam cover gasket.

• Riders will get an adrenaline-pumping burst of speed from the Milwaukee-Eight engine by installing the Screamin’ Eagle Milwaukee-Eight Stage II – Power Kit (P/N 92500058, $389.95*). A Screamin’ Eagle power camshaft starts to pile on power at 3000 RPM and produces more than 90 rear wheel horsepower from 4,500 RPM to redline in Milwaukee-Eight 107 engines. This kit is ideal for riders who want to ride the bike aggressively while downshifting to lower gears to keep the engine operating in the higher RPM range. Kit components include a Screamin’ Eagle SE8-462 cam, adjustable pushrods, pushrod covers, O-rings, and a cam cover gasket.

Screamin’ Eagle Stage III for Milwaukee-Eight = Stage I + Big Bore Pistons and Cylinders
It’s a simple recipe for performance: Increase the size of the engine and you increase power output throughout the entire RPM range. Screamin’ Eagle Stage III kits take a Stage I-equipped Milwaukee-Eight 107 to 114 cubic inches, and the Milwaukee-Eight 114 engine to 117 cubic inches. Behind a Stage III Kit, touring riders will feel like they are solo even when loaded up with a passenger and cargo. Both kits feature bolt-on cylinders that can be installed without removing the engine from the motorcycle, reducing the required time and complexity of installation. The Stage III Kits include SE 4.075-inch cylinders, forged 11:1 coated aluminum pistons, high-performance piston rings, an SE8-498 camshaft, SE performance valve springs, SE high performance tappets, multi-layer coated head gaskets, and cylinder base and cam cover gaskets. ECM calibration with Screamin’ Eagle Pro Street Tuner is required for proper installation.

• The Screamin’ Eagle Stage III Kit for Milwaukee-Eight 107 (P/N 92500056, $1,595.95*) increases compression ratio from 10.0:1 to 11:1, boosts mid-range torque up to 24 percent and delivers up to 39 percent more power when compared to the original equipment engine configuration.

• The Screamin’ Eagle Stage III Kit for Milwaukee-Eight 114 (P/N 92500057, $1,595.95*) for CVO Touring models produces 100 to 110 rear-wheel horsepower from 4,750 RPM to redline and more than 100 lb-ft of rear-wheel torque from 2,750 to 5,750 RPM.

These and other Harley-Davidson Genuine Motor Parts & Accessories are available at more than 750 authorized retail locations in the United States and online.

*Manufacturer’s Suggested Retail Price (MSRP), excluding taxes and shipping and labor cost for installation. Prices at local dealerships may vary.

Harley-Davidson Launches 107” & 114” Milwaukee-Eight Engines

The 2017 Milwaukee-Eight V-Twin will be offered in a 107″ version for Harley Tourers and Trikes and a 114″ variation for its premium CVO models. (Photos by Brian J. Nelson, and Harley-Davidson)

Stop the press! The rumors are true. Harley-Davidson has indeed developed a new engine called the Milwaukee-Eight. The eight valve V-Twin comes in both a 107” version for Harley-Davidson Touring motorcycles and Trikes and a 114” variation for The Motor Company’s top-shelf CVO line. The new valvetrain design comes with an impressive list of proposed improvements – more power, better efficiency, lower idle, less heat, and less noise.

American Iron brass Buzz Kanter and Steve Lita got a chance to speak with Harley’s Product Planning Director Paul James and Chief Engineer, New Products Alex (Boz) Bozmoski about the Milwaukee-Eight for an exclusive American Iron Magazine first look article in Issue #341 that hits newsstands Sept. 13. Additionally, American Iron Editor Lita has already gotten a chance to sample 2017 Harleys with both the 107” and 114” versions of the Milwaukee-Eight, and his first ride review will run in American Iron Magazine Issue #342. Click here for some of editor Steve’s first ride impressions.

More power, better efficiency, lower idle, less heat, and less noise – what’s not to like about Harley’s new Milwaukee-Eight 107! Find out how many of these claims are true in American Iron Magazine Editor Steve Lita’s first ride review in Issue #342.

Until then, here’s a few of the Milwaukee-Eight’s key features gleaned from the American Iron Magazine article along with the engines’ specs. If you’d like to hear the new Milwaukee-Eight, be sure to check out American Iron’s YouTube channel.

• Because these are touring machines, design emphasis was placed on rider and passenger comfort (vibration), heat control (from engine and exhaust), and functionality (improved electrics and electronics). From what we were told, Harley met these goals.

• While the engine weighs just about the same as the Twin Cam it is replacing in 2017—at least on the touring and trike models—we were told the Milwaukee-Eight is a clean sheet design, going back to a single cam configuration, with pushrod-actuated four valves per head, hydraulic lifters, and dual sparkplugs per head.

The Milwaukee-Eight 107″ heads look different for good reason. In addition to increasing from two to four valves per cylinder, the heads have been treated for advanced combustion design and flow work, said to generate almost a 50% increase in flow.


Visible in blue is the precision oil cooling passage.

The Milwaukee-Eight 107 heads look different for good reason. In addition to increasing from two to four valves per cylinder, the heads have been treated for advanced combustion design and flow work, said to generate almost a 50% increase in flow.

Pushrod-activated rocker arms control the two intake and two exhaust valves per head. Once set, valve adjustments are done for life.











• Harley said there are two versions in relation to engine cooling as well, as bikes without lowers will feature Precision Oil-Cooled engines, while bikes with lowers will employ the Precision Water Cooling system, with the radiators housed in the lowers a la RUSHMORE style. Before you get any bright ideas about retro-fitting a Milwaukee-Eight into an older bike, be aware that the engine mounting points have changed.

• The flywheel weight is the same as on the Twin Cam, but Harley has achieved 20% more rotational inertia with this engine. This aids in smoothing the driveline and producing a broad torque curve that pulls all the time. Redline is 5,500 rpm, slightly higher than a Twin Cam. A single internal engine counter-balancer is tuned at 75%, and the engine is rubber-mounted for less overall vibration to the rider and passenger.

• The heads have been treated to advanced combustion design and flow work, generating almost a 50% increase in flow. The intake and exhaust valve diameters are 40mm and 32mm respectively. Add the dual sparkplug (two per cylinder) design for a more complete burn, and you can see that this is not just a warmed-over Twin Cam design. There’s a new four-post-coil ignition with torque-based ECM with active knock sensors. There is independent control of the front and rear cylinder firing, with the front two coil outputs firing together and rear two firing together. Sequential Port Fuel injection is retained with a single throat inlet throttle body made of plastic. A bump up in compression ratio to 10:1 (107″) or 10.5:1 (114″) from the Twin Cam’s 9.7:1 means premium-grade fuel will be required.

• The single camshaft is utilized for its lower friction qualities, and it is chain driven. Thanks to a hydraulic lifter to pushrod connection from cam to rocker arm, you will never have to adjust the valvetrain from left to right, as they are now factory-set for life!

• It’s larger, more powerful, offers quicker acceleration, and produces 10% more torque. It should prove to be two to three bike lengths faster from 0-60 mph and one to two bike lengths faster from 60-80 mph in top gear.

The more powerful Milwaukee-Eight 107″ should make Harley’s tourers “two to three bike lengths faster from 0-60 mph and one to two bike lengths faster from 60-80 mph in top gear.”

2017 Milwaukee-Eight Engine Specs:
Engine:                 107″                  114″            TC 103 rubber mount
Cylinder angle:    45 degree      45 degree              45 degree
Bore:                      3.937″               4.01″                      3.875″
Stroke:                  4.375″               4.5″                        4.374″
Compression:    10:1                  10.5:1                       9.7:1
Valvetrain:      Four valves per cylinder      Two valve per cylinder
Ignition:            Four plug four coil               Two plug one coil
Torque: 114 ft-lb. @ 3250 /  124 ft-lb. @ 3250 / 104.7 ft-lb. @ 3250
Starter:                 1.6 kw               1.6 kw                  1.2 kw
Charging system: 24-25 amps / 24-25 amps / 17 amps
Fuel system:      ESPFI             ESPFI                     ESPFI
Oil capacity: 4.5 quarts      /   4.5 quarts    /          4 quarts
Idle speed:      850 rpm      /     850 rpm    /          1050 rpm

The new Harley Milwaukee-Eight will power The Motor Company’s 2017 touring motorcycles and baggers.

Harley-Davidson’s Big Twins over the Years
F-Head (JD) 1914-1929
Flathead 1930-1948
Knucklehead 1936-1947
Panhead 1948-1965
Shovelhead 1966-1984
Evolution 1984-1998
Twin Cam 1999-present
Milwaukee-Eight 2017-

Our First Ride Impressions of Harley’s New Milwaukee-Eight

Cornering on the 2017 Milwaukee-Eight-equipped Road King felt more agile than ever.

Cornering on the 2017 Milwaukee-Eight-equipped Road King felt more agile than ever.

American Iron Magazine editor Steve Lita was fortunate enough to get in a day of riding on the new 2017 Harley-Davidson Touring models featuring both versions of the new Milwaukee-Eight engine; standard 107″ and CVO models equipped with the 114″ version.

The first thing you notice when you start up the new Milwaukee-Eight is, well, the precise and consistent starting. Thanks to a new automatic compression release and a more powerful starter motor, the engine comes to life every time without a hitch or a hiccup, which can’t be said for Twin Cam models. Once the engine settles to life at a calm 850 idle rpm, you’ll recognize the traditional Harley rumble, albeit a little smoother. Don’t get me wrong, this engine is not sewing machine-boring, it still has that chugging cadence to it.

The 107" Milwaukee-Eight, staying true to Harley's Big Twin tradition while leaping forward.

The 107″ Milwaukee-Eight, staying true to Harley’s Big Twin tradition while leaping forward.

Click the bike into first gear and release the clutch, and you’ll be pleased with the easier feeling on your left hand. Roll on the throttle easy, the Milwaukee-Eight smoothly pulls this heavyweight up to speed. But gun the throttle, and get ready for an aggressive bark from the stock exhaust. Thanks to less drivetrain noise and the added cubic-inches, the exhaust emanates an aggressive tone. After my first ride I commented to Harley engineers how much I liked the sound of the bike.

Unfortunately, I didn’t have access to a timed acceleration course, but suffice it to say the seat-of-the-pants-feeling under hard acceleration was that the new bikes pull away from a stop or roll on at speed harder than before. This Milwaukee-Eight pulls hard all the way to the 5500 redline, and I found the rev limiter many times when not judiciously watching the tach. I felt consistent thrust all the way up the tach range without the power petering off. It just pulls, pulls, pulls, and then smack! You’re on the limiter. Step up to the larger 114″ Milwaukee-Eight, which is available only in the CVO models, and get ready for a kick in the butt over the 107″ version; you will definitely feel the difference in power output.

And the 114" Milwaukee-Eight, a CVO-only option that will blow your socks off.

And the 114″ Milwaukee-Eight, a CVO-only option that will blow your socks off.

All of that is great for straight-line riding, but what happens when you throw the new Touring models into a curve? Much improvement has been made to this line of bikes, and the new 2017 models can handle some twisties better than ever before. New front fork updates feature SHOWA Dual Bending valve (SDBV) technology, which is similar to current cartridge fork inserts, but more adept for mass production use. Out back is a hand-adjustable SHOWA emulsion shock. Turn the adjustment knob 23 times to allow for 25mm of total adjustment. No more worrying about blowing out air shocks. Confidence in riding through corners at high speed is greatly increased.

The 114" CVO Touring Model handles better than you could imagine for a Big Twin.

The 114″ CVO Touring Model handles better than you could imagine for a Big Twin.

My overall riding impression of these new Milwaukee-Eight-powered models is that Harley has taken all the right feelings and emotions of the previous engine and refined them, doing so with new high-tech components. The looks of the engine are right. It’s not some foreign, radical departure. Yet under the skin, the internal components work in better harmony than before. I think of this engine as a well-sorted Big Twin. It’s better than you ever thought the Big Twin family could perform.

For the full first ride review of the all-new Milwaukee-Eight Touring models, pick up a copy of Issue #342. In Issue #341, on sale 9/13, we give you everything you need to know about the new engine platforms.