Harley-Davidson Milwaukee Eight engine debuts

The wait is over. Harley-Davidson has debuted its new Milwaukee Eight engine, the newest powerplant for their Big Twin lineup.

First, some numbers: As predicted, there’s a 1750 cc (107 ci) and 1860 cc (114 ci) version of this engine. The standard motor will have oil-cooled heads, but there will also be a version with liquid-cooled heads. As was also predicted, there will be a single cam and two spark plugs per cylinder, and four valves (hence the name Milwaukee Eight). Those valves are said to offer 50 per cent better air flow, which also means there’s a new 55 mm throttle body.

Better airflow also resulted in better fuel efficiency, Harley-Davidson says (we haven’t heard how much better), but also allows for more power — the touring lineup supposedly has 10 per cent more torque available now, which would theoretically place them in the 156 Nm range. We haven’t seen horsepower figures for the new motors yet.

Some more numbers: Bore and stroke are 100 mm and 111.13 mm respectively for the oil-cooled 1750 cc (107 ci) motor. The liquid-cooled 1860 cc motor has a 102 mm bore and 114.3 mm stroke. We haven’t seen numbers for the other variations of the motor.

While the engine is still rubber-mounted, a single counterbalancer removes 75 per cent of vibration at primary idle, Harley-Davidson says; supposedly, prototypes actually featured 100 per cent vibration control, but lacked the feedback MoCo customers wanted. Engineers lowered idle speed to 850 rpm, but managed to improve charging system to 24 amps at idle (up 50 per cent) and 30 amps at 1,050 rpm.

Despite gossip the new engine wouldn’t have self-adjusting hydraulic valves, that isn’t the case. The Milwaukee Eight continues to use self-adjusting valves, and Harley-Davidson says they will not need adjustment over the lifespan of the motor.

Harley-Davidson also re-designed the exhaust routing, so riders aren’t cooking the inside of their legs in stop-and-go traffic.

The new oil-cooled 1750 cc motor will initially be available in Harley-Davidson’s touring lineup, as predicted (Street Glide, Road Glide, Electra Glide, Road King, Tri Glide). The liquid-cooled 1750 cc motor will power the Ultra lineup (Ultra Limited, Ultra Limited Low, Road Glide Ultra, Tri Glide Ultra) and the liquid-cooled 1860 cc motor will power the CVO lineup (CVO Street Glide, CVO Limited).


Check out all the pics that go with this story!


  1. It’s telling that you take offense to my comments but you’re clearly perfectly ok with the “Harley Faggotson” comments on here. My comments are directed at those types, who need to speak with such rancorous persistence against an otherwise really successful company. One doesn’t need to even know of Freud to see that other issues are at play. In all my years I’ve known these types personally, and one or many or all of the reasons I’ve raised rung true. I suspect with you it’s the “I’d look like too much of a douche” reason 😉

    Otherwise I got 8 other toys not branded HD in my possession, so I’m not brand blind. And of course I get that Harley is not the bike of choice for many – there’s a bunch of bike types and even brands that I certainly don’t prefer. But I never felt the need to attack them or their owners with such distain.

    • “It’s telling that you take offense to my comments but you’re clearly perfectly ok with the “Harley Faggotson” comments on here.”
      No, I take offense to how you phrase your comments and how you make assumptions on all those who don’t agree with you. If you want to ride a Harley, that’s your business. If people choose to criticize your choice, you seem to take it personally. So, about that Freud comment…. 🙂

      And really, we don’t care how many toys you have. Happy riding!

  2. Now that the speculation is over, they all seem like worthwhile changes. Though I guess it was more fun to speculate for some…

    It’s downright funny seeing all the haters & internet toughguys on here and how hard they try – the ones who’ve never ridden a modern one / can’t afford one / not allowed to buy one / not sure they can actually pull a u-turn on one / think they’d look like the doofus that they are on one / etc…

    • Geez Rui, do you ever make an effort to NOT insult people who don’t agree with you? Look, lots of people don’t like Harleys precisely because the attitude you display here is the same general attitude displayed by every other Harley owner (with some notable exceptions, Willy and BBB being two of them). Can you accept that, for some people, a Harley is not their bike of choice?
      But to your pointss: I’ve ridden a modern one, I can afford whatever the fuck I want to buy, I am certainly “allowed” to buy one, I can pull a u-turn, and lastly, EVERYONE looks like a doofus when they’re on one. 🙂

  3. Not many kind words for Harley so far. Like most manufacturers they have a few models I like and some not so much. I know some folks love them and would buy nothing else. They must be doing something right as they have been around forever and continue to sell well.

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