Few motorcycle companies are as tied to a single engine configuration as Harley-Davidson. The iconic V-Twin engine that powers every bike in the lineup has a lineage that reaches back over a century, and any deviations from the V’s status quo through Harley’s history are rare and brief.
So when Harley-Davidson rolls out an entirely new iteration of their brand’s mechanical heart and soul, as they have now done with the new Milwaukee-Eight motor, it’s big news and you’d better believe they took the time to make it work right.
The new plant, so named because it features heavy-breathing four-valve heads (for a total of “eight” valves), will be available in 107 and 114 cubic-inch variants (1750cc/1870cc), with the bigger models more likely to be found in the big-rig touring bikes like the Ultra Classic, where it will also receive H-D’s “Twin Cooled” air/liquid cooling system to keep the heat down. Models using the 107ci version will use either the water/air or an oil/air cooling system depending on the model.
In a nutshell, the new motor makes 10 percent more torque than the Twin Cam power plant it replaces, and while Harley didn’t (and usually doesn’t) give any horsepower figures, it’d be fair to expect a bump in ponies as well. But after riding the hopped-up hot rod 110ci Twin Cam Low Rider S recently, I’d have to say more of either is going to work just fine for long-time Harley riders and anyone else who decides they want to get in on the fun.
Harley-Davidson was kind enough to give The Manual some time to chat with H-D Museum VP Bill Davidson, great-grandson of one of the company’s founders, William A. Davidson, about the new engine and the bikes it will be found in for the 2017 model year (lightly edited for brevity).
The Manual: How long has the engine been in development?
Bill Davidson: Well it started several years ago and our process is very thorough, obviously, to produce the world’s best motorcycle engine, the Milwaukee Eight. What we start with is gathering a lot of customer and dealer input as to what they would like to see in the next-generation V Twin from Harley-Davidson. And once we get that information, our experts in engineering, manufacturing, styling, they go to work to make a motor that truly delivers – exceeds, actually – our customers expectations. And I have to tell you, I’ve had the opportunity to ride the Milwaukee Eight and it truly delvers the most power, the responsiveness of the
Traditionally, when going from a two-valve head to a four-valve head, a engine can take a hit to the torque output, but you’re claiming a torque boost. How is that accomplished?
If you think of the V Twin as an air pump, when we went from two valves to four valves, it allows us to increase the amount of air on the intake stroke and with the four-valve exhaust, to get that burnt gas out of the engine much more efficiently. So you’re enhancing the overall “workability,” if you will, of the engine and that produces about ten percent more torque. And in some of the other designs of the motor, it’s actually mechanically more quiet, and that has allowed us to enhance the exhaust note – that “potato-potato” – that V-Twin sound Harley is known for all over the world. And so the overall package truly is phenomenal… I rode it and it truly delivers.
Is the fuel management system upstream air mix injection, or are you using direct injection now?
We’ve been using direct injection on our Twin Cam and the Milwaukee-Eight is direct injection.
One of the things I was impressed with last year when Harley had their press ride in Portland was that there is a lot of tech in the bikes now – the ABS system built into the hubs, the Twin Cooling system and so on. But the tech is very well hidden, so the bikes retain a clean, even vintage look. How important is that to your customers? What have they been telling you?
That is something we work very very hard at. You know, my dad Willie [Willie G. Davidson] once coined a phrase: “form follows function, but both form and function report to emotion.” And when you think of a motorcycle, a
Which models did you ride and which model did you enjoy the most?
We were at a test track with a whole array of touring motorcycles that the new motor is in, and I rode the Road King, the Street Glide, the Ultra Limited, and I was speechless. I gave our chief engineer a bear hug (laughs).
What’s the status of Project Livewire (Harley’s electric motorcycle project)?
Livewire is alive and well, no pun intended. We’re very very excited about that motorcycle, we continue to develop it. We’re following a little bit different path on that bike. We actually had about 30 (!) prototypes which we toured around North America and then Europe for our customers and our dealers. We have a list of items that we are putting into process, if you will, that we need to develop or change, to ensure that we create a phenomenal
Do you think it will ever become a Harley-Davidson product, or is it just a project?
The Livewire is a motorcycle that we’re going to continue to develop. We don’t have a specific launch time but we are developing it and it is an important project for Harley-Davidson.
We are hoping to have riding reviews of some of the new bikes here on TheManual.com in the near future. All photos courtesy of Harley-Davidson.