Milwaukee Eight

Article By: Chris Callen

Photos Courtsey Of: Harley-Davidson

Originally Published In The  December 2016 Issue Of Cycle Source Magazine

For fifteen years the Motor Company has led their charge through the heavyweight motorcycle category with the Twin Cam engine as the driving force behind their iconic brand. With a few generations of that design behind them now, where only slight improvements have been made to address rider feedback, a change was long overdue. For the 2017 model year Harley-Davidson® is releasing what we at Cycle Source believe to be an absolute game changer in their touring motorcycles. Of course, the most notable is the brand new engine family; the Milwaukee Eight, but the rest of what has been addressed on these new bikes adds up to a complete redesign. Harley-Davidson ® would take the comments and concerns of both current Harley owners and of those who were considering a Harley. Their engineering team would put aside their own personal aspirations and would work with one goal, to make the perfect motorcycle to meet the demand in the real world today. What they came out with was not only a bike that is a blast to ride, power throughout the range, completely responsive new suspension, upgraded charging system, new lower profile rider position, better heat management, seriously a better motorcycle. Last month the good folks at Harley- Davidson® had all of the American Editor’s out to north Washington to give us the space to conduct proper scrutinizing of these new machines. We will be offering standard test ride articles of each one of these motorcycles in the months to come, but for this issue let’s start with a full overview of the new features starting with the new engines named the Milwaukee Eight.

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 oilcooled 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. What would start as a completely blank canvas, according to Alex Bozmoski, Harley-Davidson® Chief Powertrain Engineer, would see a new and selfless process from everyone involved in this project. A level of give and take from each department across the factory to come together in cooperation of what was best for all.

Let’s start off by stating what the new engine would not be, it was agreed upon by everyone involved that this new design couldn’t be a departure from the classic look and feel of what makes a Harley a Harley. To that end they retain the 45-degree V-Twin and they did go back to a single cam. While this gives the motor less moving parts and a quieter mechanical operation overall, the question most of us asked right off the bat was why keep the chain drive then? Believe it or not the chain is actually quieter than gear or direct drive. All through this motor design the engineers cut mechanical noise wherever they could so they would be able to maximize exhaust noise. The result was a much deeper overall sound. Of course this is still a stock exhaust system but with that in mind they killed it. Now, what they did change while keeping an ear to the ground from a historical standpoint is nothing less than amazing from Harley. The new heads are, of course, four valves per and boast fifty percent more intake and exhaust flow capacity. This gives the MI8 a big boost in performance but would increase an already sensitive heat issue. To get this to work they would need to employ new cooling principals for their original air-cooled designs. While Harley purists still seem to resist the idea of a fully water-cooled engine, what the engineers came up with might be the perfect crossover. In the new system coolant is pumped through a heart shaped passage that surrounds the area between the valves of each cylinder head. This small section of head material is heated by both the combustion on the piston side and the exhaust on the valve side so by design it is prone to excessive heat. The heads are also dual plug for more efficient combustion and that combined with a shallower valve pocket also goes a long way to dealing with heat.

Also new to the MI8 is the addition of knock sensors to the fuel injection tuning system. With a 55MM Mikuni throttle body, 5mm bigger than previously used, combined with head mounted knock sensors give the new engine the ability to fine tune the ignition timing for each cylinder. By keeping the ignition timing near the edge of detonation it delivers more power with less heat. As a side note, it also burns cleaner and give off less emissions, something the company needed to deliver a motorcycle with common performance characteristics world-wide. While company personnel explain that touring riders aren’t concerned with fuel economy they did mention that the MI8s are the same or slightly better in that department when compared to the Twin Cams. The new engine also has a counterrotating balancer that reduces the vibration at idle speeds up to 75%. They actually had reduced more vibration than that but got feedback from existing customers that it didn’t feel like a Harley anymore so they backed it off to keep some of the inherent traits that make people love the brand. They produce 10 percent more torque than their predecessors and idle all the way down at 850rpms. That’s a big deal for anyone who came from Evos and had to adjust to the much higher idle speeds of the Twin Cam. This was accomplished by upgrading the charging system. Under the old system the lower idle speed would actually go into a state of negative charge. With the much heavier demands put on a motorcycle charging system by today’s touring rider this had to be improved. The new system is reported to have 50 percent more output to the battery at idle.

Anyone having serious miles on a Twin Cam can also relate to the gear lash in the transmission that gives you that little rocking feeling at slow, or what Harley calls parade speeds. To address that in the new touring bikes they came up with an additional gear that eliminates backlash. It was immediately noticeable on our riding. Another feature for Harley in the new model release was the rider position. For many non-American riders, the average rider height is an issue. In order to get this lower position, they reduced the width of the motorcycle giving shorter riders a more flat footed stance. This was due to a narrower primary from a thinner clutch pack. It’s pretty neat since you don’t really notice it until it’s pointed out to you and gives a reported 7% reduction in clutch effort as well. Many of us have waited for a better suspension solution from the factory for quite a long time. Unfortunately, this has only been achieved through the aftermarket until this release. In addition to all the go power on the MI8s, these new bikes have real world appeal for anyone who is familiar with real suspension. The new emulsiontechnology rear shocks offer up to 30 percent more pre-load adjustment over previous, with a single knob to adjust pre-load. The best part is there is no leak down and no special pump that must be used as in the standard touring shocks of the past. The front suspension is the real news here too, much like tuned suspensions from other types of motorcycles both on and off the track, these new Showa® SDBV™ suspension technology forks deliver the damping performance of a racing-style cartridge fork with linear damping characteristics and reduced weight.

Unlike previous engine family releases Harley-Davidson was so far ahead of the ball on the Milwaukee eight that they actually have the entire line of Screamin’ Eagle® Performance components available as the new models are hitting the showroom floors. They offer a full selection of street-legal performance components for the Milwaukee- Eight™ engines, including Screamin’ Eagle® Milwaukee-Eight™ Stage I, II and III kits that deliver up to a 24 percent increase in torque over the stock engine. So, let’s get to the riding impressions part. We were given an opportunity to ride all of the new touring bikes with all the different combinations of engine size and cooling options. I want to thank Harley-Davidson® for an incredible few days of riding along the north western coastal area in Washington. Since I have over 200,000 miles on a Twin Cam Ultra Classic™, I figure the best appleto- apple comparison would be that I start off with the Ultra. Right off I was really impressed with the look of these new bikes. One of the cats from Harley said that they wanted them to have the same classic looks of a Harley from 100 feet away and it did. From two feet away it looks fresh and modern with new features that any long time Harley touring bike fan will love. Like the new saddlebag latch system, no way to explain how cool this is. It is 100 percent better than the old system and 100 percent one hand operation. The cooling system is hidden in a way that makes it almost unnoticeable. And before you diehards get started, no it’s not like your hardtail stripped down Knuckle, but that’s not what we’re talking about here. This is a real cross-country touring machine and from my perspective, a great bike.

So we headed off into the countryside to see what these bikes would do. The one thing I noticed was that there wasn’t a place where I asked this bike for power that it didn’t have it. If I came out of a turn in a gear too low, all I had to do was roll on the throttle and it pulled out. If I was rolling down the highway and wanted to pass traffic, it was a twist away. Harley touts quicker acceleration of 2-3 bike lengths faster from 0-60 mph and 1-2 bike lengths faster from 60-80 mph in top gear. What matters to the rider is that the bike has balls when you need it, no matter what the situation. The was no lope, no lag, just good old fashion fun motor bike riding. On these press events there are always spots where you set up to get good photos. This usually requires waiting in line to go one after another back and forth through a section of road where the photographers are set up. In this case that was the perfect environment for our testing purpose. The section where we staged for photo runs happened to be one of the best uphill/downhill section of twisting turns. We beat the hell outta these things in the bends. We employed super hard acceleration, throwing the bikes back and forth in the turns and different gear selections to see how it would respond. The first thing to report here is that the suspension is everything they claim it to be. There is no walk through the bends from the front suspension and no pogo from the back. I found it to be responsive and recovered quickly. The other thing to report was the power delivery. These bikes are smooth and fun. No matter what gear I was in coming through the bends I could power through. On the other side the power continued for quick exit acceleration.


The clutch felt fine, the gear lash was gone, and the audio system was great but I was more concerned with more of the issues this motor was supposed to best the Twin Cams in. The heat issue to be more specific, the heat issue was absent. One time I can tell you this was more apparent than any other was when it rained a little bit and left some standing water on the road. Typically, on my Twin Cam this is where I would get ready for a steam bath, you know, after running through a puddle and the entire bike steams for the next ten miles or so. Yeah, that didn’t happen with the Milwaukee Eight. In fact, there was never a time over two days where I noticed any discomfort from the heat, it just wasn’t there. Hopefully this initial report gives you an idea of what the Motor Company has going on and motivates you to get out to a dealership today to take a look at one for yourself. As for me, my official editorial position is “If you own a Twin Cam, sell it quick.” Of course there will be the normal, manufacturing hiccups to deal with, like any new product but baring any large failures, which should have presented themselves in the rigorous testing process prior to this release, this should be exactly the thing Harley needed to retain the lead.

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