6 Things to Know About the New Harley-Davidson Milwaukee-Eight
1. Eight Valves Mean More Power and Better Mileage
The engineering designed into the new engine brings Harley current with the state-of-the-art, with four valves and two spark plugs per cylinder. The redesigned combustion chambers and ports mean vastly improved thermal efficiency, greatly increased intake and exhaust flow, and countless other improvements that will get you 10% more usable torque while delivering up to 11% better fuel economy on a tank of gas. The new motors are also designed to run cooler so the computer doesn't have to limit your power and cut the fun short on hot days when fully loaded.
2. Vibration is Reduced but Not Eliminated
If you are thinking about joining the ranks of the Harley faithful but are hesitant about dealing with the handlebar-shaking vibration, you will be pleased to know that the Milwaukee-Eight incorporates an internal counter balancer and rubber engine mounting. If you are Old School, be assured that your engine will still feel like a H-D big twin — they did not engineer all of the vibration out, stopping at about 75% so you can still feel the thrum of the engine as you ride.
3. Air/Oil Cooled or Liquid Cooled
The new Milwaukee-Eight engine comes in two versions — one features precision oil-cooled cylinder heads and the other has water-cooled cylinder heads and radiators ("Twin-Cooled" in Harley-speak). This mirrors what they did with the twin cam motors in the Project Rushmore bikes. For the time being, the engine is only in H-D's touring bikes and trikes; Street Glides, Road Glides, Electra Glide Ultra Classics and Freewheeler trikes get the oil-cooled version, and Ultra Limiteds, Road Glide Ultras, and Tri Glides rock the Twin-cooled. In the picture above, the blue represents the coolant passage that water flows through around the dual exhaust valves.
4. The Best Rider and Passenger Comfort Ever
The Milwaukee-Eight fleet delivers the highest rider and passenger comfort levels ever offered on a Harley, by design. In addition to its previously noted improved power, cooling, and vibration management systems, the Eight also features re-positioned exhaust pipes so that their heat is farther from the rider and passenger. A new chain-driven single cam also reduces mechanical noises throughout the rev range, so you can enjoy the noise of the exhaust more. The new primary drive design is narrower, to give your legs a straight shot from the seat to the ground, something shorter riders will really appreciate.
5. Improved Charging to Support Modern Accessories
Harley has increased the charging capacity of the Milwaukee-Eight by a full 50% over its predecessors. Last year the charging system put out about 17 amps at idle, but the new one puts out nearly 25 amps and the idle speed is 200 rpm lower. Once you start to rev it, you'll have 30 amps at the old 1050 rpm idle speed. No longer will you have to decide between upgrades to your audio, heated gear, or lighting accessories — do them all and enjoy your ride to the fullest. The starter is stronger, too, so it can support larger bores and higher compression ratios, and the new design incorporated automatic compression releases as well.
6. Two Sizes: 107 or 114 Cubic Inches
The standard touring bikes get the new 107-cubic-inch Milwaukee Eight v-twin, with about 111 lb-ft of torque, which is plenty. But if that is still not enough, the motor company has a special, new CVO version of the motor displacing 114 cubic inches and putting out 124 lb-ft of torque. You can get this maximum motor in either the 2017 CVO Street Glide (pictured) or the top bike in this year's lineup, the CVO Limited. That's an extra 10 lb-ft of torque, and it comes 500 rpm lower in the power band for instant acceleration.
For maintenance and repair guides for your Harley, browse our technical How-to articles right here at HDForums.com!