Editor’s Note: When the new M-8 hit the news, we were all curious as hell. Would Harley buckle to some government regulation and build a liquid-cooled engine? Weren’t they still dialing in the Twin Cam? Would the new engine deal with Twin Cam issues? And finally, wow, how time flies. Seems like yesterday, the Twin Cam was introduced.
The crew at Bikernet started to ask questions. Unfortunately, no one in the aftermarket had any issues yet. Reviews were strong and impressive. Acceleration was smooth and deliberate. The bikes handled better, and we were immediately excited about the single cam, but it was driven by a chain again? We started to ask questions.
Below you will read some factory info. I reached out to the H-D but was unable to collect answers to our questions. But this weekend at the Long Beach Show, I was able to corner an engineer who worked on the project, Matt Mueller, who has worked for the factory for 20 years. He was elated with the new platform and his face lit up as he discussed his pride in being involved in another iconic Harley engine. Plus, he’s an Evo fan.
Below you will see where I have added additional information based on our conversation and questions from the industry.
The all-new Harley-Davidson Milwaukee-Eight engine, ninth in the lineage of the company’s iconic Big Twin engines, delivers more power and an improved motorcycling experience for riders and passengers while retaining the iconic look, sound and feel of its predecessors. An all-new design, the Milwaukee-Eight engine offers quicker throttle response, more passing power, purer sound, a smoother ride and more of the feeling riders want from a Harley-Davidson Touring motorcycle engine.
“The guiding principle behind the Milwaukee-Eight engine was our voice of customer research from every region of the world,” said Scott Miller, Harley-Davidson Vice-President of Styling and Product Development Strategy. “Riders asked us to create a new engine designed to enhance their motorcycle touring experience in every way. Those same voices also demanded that we stay true to our legacy and respect the defining elements of a Harley-Davidson V-Twin. It was a big challenge, but one we’ve met. With the Milwaukee-Eight, a new era of Harley-Davidson power, performance and innovation has been forged.”
New Milwaukee-Eight engines will power every 2017 Harley-Davidson Touring and Trike motorcycle model. Milwaukee-Eight engines will be offered in two displacements and three variations:
Milwaukee-Eight 107 (107 CID, 1750cc) featuring precision oil-cooled cylinder heads for the Street Glide/Street Glide Special, Road Glide/Road Glide Special, Electra Glide Ultra Classic, Road King and Freewheeler models.
Twin-Cooled Milwaukee-Eight 107 (107 CID, 1750cc) featuring liquid-cooled cylinder heads for the Ultra Limited/Ultra Limited Low, Road Glide Ultra and Tri Glide Ultra models.
Twin-Cooled Milwaukee-Eight 114 (114 CID,1870cc) featuring liquid-cooled cylinder heads for the CVO Limited and CVO Street Glide models.
More Power
Each Milwaukee-Eight engine produces 10 percent more torque than the engine it replaces in Touring models. In addition to increased displacement, the Milwaukee-Eight engine features a higher compression ratio and four-valve cylinder heads with 50 percent more intake and exhaust flow capacity.
A member of the industry pointed out that there are currently no ways to adjust the tappets. Matt said the valve seat tolerance is very tight, plus the pushrods are attached to non-adjustable hydraulic lifters. The lifters will allow for tappet, valve or valve seat wear. I’m sure some performance guys will dispute this, and James Simonelli pointed out that every other motorcycle valve system of this nature in the industry contains tappet adjustments.
We have proposed a hydraulic lifter theory and practice article with the team at JIMS machine. I’m looking forward to it. I have questions about how hydraulic lifters work and how accurate they are.
The valve train requires no adjustment, as the design of the rocker arms enables valve lash to be set at the factory for life.
Dual spark plugs for each cylinder contribute to more-efficient combustion. A single chain-driven camshaft is lighter, mechanically less complex and creates less friction and noise.
I questioned the chain technology, since this was one of the major problems with the Twin Cam. Also, I have always loved the simplicity of the Evo single cam, gear drive technology. “The hydraulic cam tensioners solved that issue,” Matt pointed out. “Also, the chain deals with noise issues.” Then he pointed out his admiration for the Evo platform, but assured me of the futuristic qualities behind the new M-8.
During the Evo, era a couple of builders designed and manufactured 4-valve heads including Quantum Cycles. Here’s one still in existence around Feuling Technology:
Revolution Performance Motors has introduced the RPM Hemi 4-valve heads for the Evo V-twin and early Twin Cam engines, Twin Cam EFI kits are currently being tested and will be available soon. If someone asks, “That thing got a hemi?” just install these heads and you can say yes. Sweet! The heads bolt directly on to the stock engine. The only changes required are valve clearance pockets must be cut into the pistons and the exhaust must be modified.
RPM has either conversion kits or complete engines in several displacements. There’s also an intake plenum that mounts two carburetors. The second CV carb serves as a vacuum secondary for high RPM runs. The heads fit any bore size from 3.5 to 4.25 inches. The hemi combustion chamber and center location of the spark plug, as well as less spark advance, allow compression to increase from the stock 9:1 to over 11:1. Evo kits start at $2995, Twin Cam kits from $3099.
Need Parts and Accessories for the Feuling 4 VALVE, American Quantum Motorcycles? Contact: Jeff Starke 262-501-4500 or jeff@masterbikebuilders.com
“The Milwaukee-Eight engine retains the classic Harley-Davidson 45-degree V-Twin design,” said Alex Bozmoski, Harley-Davidson Chief Powertrain Engineer, who led the development team. “It also retains the power characteristic that is the real legacy of the Harley-Davidson Big Twin: strong low-end torque with a broad, flat power curve through the mid-range that’s ideal for the Touring motorcycle rider.”
Quicker Acceleration
The Milwaukee-Eight engine weighs the same as the engines it replaces, so all of its extra power contributes directly to improved acceleration performance.
The Milwaukee-Eight 107 accelerates 11 percent quicker 0-60 mph, equal to a two to three bike length improvement, and 11 percent quicker from 60-80 mph in top gear, equal to a one to two bike length improvement, compared to the Twin Cam High Output 103.
The Milwaukee-Eight 114 accelerates 8 percent quicker 0-60 and 12 percent quicker 60-80 than the Twin Cam 110.
Heat Management
The Milwaukee-Eight engine offers improved rider and passenger thermal comfort due to reduced heat absorption, increased heat rejection and a redesigned exhaust system.
Each Milwaukee-Eight engine features a precision cooling strategy based on the specific demands of the motorcycle model, using a targeted flow of either oil or liquid coolant around the hottest areas of the cylinder heads.
A new knock sensor for each cylinder enables more precise timing control.
The rear exhaust pipe is repositioned and the exhaust catalyst is relocated to move heat away from the passenger. Idle speed is lowered from 1,000 rpm to 850 rpm.
Almost a gallon of oil will pass through the engine each minute due to an improved and enlarged oil pump. The cooling aspect is primarily around the exhaust port, which is the hottest portion of the engine.
Improved Fit
A new, slimmer primary drive cover and the low-profile shape of the air cleaner cover provide improved rider legroom around the engine and an easier reach to the ground for many riders. All Milwaukee-Eight powered models are fitted with an Assist and Slip Clutch with improved hydraulic actuation that reduces clutch lever effort by 7 percent.
Reduced Vibration
The rubber-mounted Milwaukee-Eight engine features a single internal counter balancer that cancels 75 percent of primary vibration at idle for a more refined feel and more comfortable experience for rider and passengers while retaining the classic character of Harley V-Twin engines.
I asked Matt about the counterbalancing system between the crank. By the way, the crank configuration is traditional but the crank pin is larger, allowing for more rod bearings. Enhanced oil flow should make for a happier, longer-lasting engine.
The new counterbalancer is so efficient that initially, it removed virtually all engine vibration, which didn’t sit well with test riders. “They wanted to know they were riding a Harley,” Matthew said, “and not a touring bike built overseas.” So, the factory adjusted the vibration level to be just enough but not too much or damaging vibration.
Richer Exhaust Note
Lighter valves, a single camshaft, optimized cover designs and improved driveline components eliminate mechanical powertrain noise.
The engine intake and air cleaner are designed to reduce intake sound while ensuring maximum airflow. As a result, the new Milwaukee-Eight engine is mechanically quieter, enabling a richer exhaust tone, and it meets all global noise and emissions standards while allowing the unmistakable rumble of its exhaust note to resonate.
Improved Charging
The Milwaukee-Eight engine charging system delivers 50 percent more output to the battery at idle to better support the power demands of Touring riders, including accessory lighting, performance audio, and heated gear and other accessories.
New Engine Styling
The Milwaukee-Eight engine features sleek, modern styling that respects the heritage of previous Harley-Davidson Big Twin engines.
“The Milwaukee-Eight engine is styled to project power,” said Brad Richards, Harley-Davidson Director of Styling. “I compare it to the back of a swimmer, lean in the waist but broad and muscular in the shoulders.”
“The rocker covers look like skin stretched taut over muscle, like the rocker arms are about to burst out of the engine,” said Richards. “For the first time since the Knucklehead, the rocker covers reflect the action going on below. And they are massive. When you sit on the bike, you can look down and see more of this engine.”
We’re proud to introduce the next generation of Harley-Davidson V-Twin engines to our Touring line: the all-new Milwaukee-Eight 107 and Milwaukee-Eight 114 engines.
Their iconic look, distinctive sound and massive torque make them instantly recognizable, but the Milwaukee-Eight 107 and Milwaukee-Eight 114 engines take the Harley-Davidson V-Twin to a place it’s never been.
They’re the most powerful, coolest-running motors we’ve ever built. Smoother, stronger and more durable. With crisper throttle response and truer, cleaner sound. Four valves per cylinder, single chain-driven cam, dual spark plugs, counterbalanced and rubber-mounted.
Developed and proven over countless miles and millions of hours. Every single part is new, engineered to give you more performance and more of the feeling you want from an engine.
