Nothing quite feels like a Harley engine under the saddle, and with the American motorcycle maker having added the “Milwaukee-Eight” to its long heritage with Big Twins, our leather-wearing days are far from over.
However, you might be here as you’re undecided whether to go for the 107 or the 114, which one is more likely to help you achieve nirvana in a twist of the throttle, and whether or not you’ll even prefer either over the more classic engines (no bias here!).
The only way to find out is by pitting these two new Big Twin power plants against each other in this comparison guide, so zip up your leather jacket and come along for the ride!
History of Milwaukee-Eight 107 and 114 Engines
Harley-Davidson has been making V-Twin engines since the renowned American motorcycle company’s first steps in the 1900s (that’s 120 years at this point), and now the Milwaukee-Eight marks the ninth iteration of the engine configuration.
First unveiled in 2016 for certain 2017 models, the Milwaukee-Eight is the 9th-generation V-Twin engine by Harley and is the successor to the aging “Twin Cam” series of engines produced since 1998.
The Milwaukee-Eight engine’s name is derived from it having eight total valves and being manufactured in, you guessed it, Milwaukee, Wisconsin.
Throughout this article, we’re going to mainly focus on the 107 and 114 versions of the Milwaukee-Eight, although it’s still worth mentioning that a 117 version is available as well.
Both the Milwaukee-Eight 107 and 114 utilize a 45-degree radial V-Twin configuration. These two engines have been primarily used to power various Harley Touring, Trike, and Softail motorcycle models since their introduction.
Comparison Between the Harley Milwaukee Eight 107 vs 114 V-Twins
If you prefer a bit more low-end torque at the cost of some fuel economy from your Milwaukee-Eight, then go for the 114 over the 107.
The 114 also allows for slightly sharper lean angles and has a bigger bore and longer stroke than the 107, though both come standard with Harley’s ESPFI system.
But to better compare the Milwaukee-Eight 107 with the 114, we’ll be looking at each of their power and torque figures, engine capacity, compression ratios, fuel consumption (mpg), stroke type, and ESPFI systems in more detail.
Horsepower
First things first, it’s important to mention that Harley-Davidson did not release official horsepower numbers for any of the Milwaukee-Eight V-Twins. However, dyno results from third-party testing methods are available.
When measured at the rear wheels, the Milwaukee-Eight 107 makes about 81 rwhp (rear wheel horsepower), while the 114 makes 5 more than that at 86 rwhp.
When measured at the crank, which is what most vehicle manufacturers do, the 107 produces around 93 hp, while the 114 manages to make 101 hp.
Of course, such horsepower figures may vary depending on the condition of the motorcycle and even the exact dyno that you use. Thus, use the abovementioned figures only as a general guide to how much power your Harley potentially makes.
Torque
Compared to horsepower figures, torque figures for the Milwaukee-Eight (and any other Harley engine) are a lot more publicly available from the get-go.
Due to the low-revving nature of the Milwaukee-Eight V-Twin, torque figures look a lot more impressive compared to horsepower ones, with the 107 version making 111.4 ft-lbs at 3,250 RPM.
The 114 version, on the other hand, unsurprisingly makes significantly more torque at the same RPM at 124 ft-lbs.
While you may think that more torque equates to a more brutal throttle response, it’s actually not quite the case between the two Milwaukee-Eight engines in question.
Though the 114 is ahead in torque figures, in real-world driving, the 107 actually responds and uses its available torque just a bit more instantly in the low revs due to its shorter cylinder stroke.
Engine Displacement/Capacity (CC)
Just knowing which version of the Milwaukee-Eight engine you have will already let you know its engine displacement or capacity. Sometimes, engine displacement is also referred to as the “engine size”.
Thus, the Milwaukee-Eight 107 version simply has an engine capacity of 107 cubic inches, or 1,750 cc (cubic centimeter).
By comparison, the 114 engine will have a slightly larger engine displacement or capacity at 114 cubic inches, or 1,868 cc.
But despite one being bigger than the other, the Milwaukee-Eight 107 and 114 are both classified as Big V-Twin engines by Harley, contrary to small V-Twins like the older 1,000-cc “Ironhead” engine from the 80s.
Compression Ratio
Modern Harley engines typically have a minimum compression ratio of at least 9.5:1, which is considered quite low for modern motorcycles but is actually the minimum needed for Harleys to make optimum power.
However, the Milwaukee-Eight 107 and 114 V-Twins have slightly higher compression ratios of 10.0:1 and 10.5:1 respectively.
When compared to other engines, these compression ratios for the Milwaukee-Eight V-Twin are almost twice as high as that of Harley’s “Flathead” engine from 100 years ago.
But of course, if you compare the Milwaukee-Eight’s compression ratio to something like a high-revving 1.3-liter Suzuki Hayabusa engine at 12.5:1, then the former’s doesn’t seem like much.
Fuel Consumption
Fuel consumption ratings for the Harley Milwaukee-Eight can slightly vary between versions and also the exact motorcycle model the engine is fitted on, though there are some general ratings listed for both the 107 and 114.
The Milwaukee-Eight 107 engine can achieve a combined gas mileage (city/highway) of 45 mpg, whereas the bigger 114 engine is rated at 43 mpg instead.
Bore and Stroke
When looking at the cylinder bore and stroke of the two Milwaukee-Eight V-Twins, the 107 has smaller dimensions in comparison to the 114.
The 107’s bore measures 3.937 inches in diameter, which is only a mere 0.063 inches or 1.6 mm smaller than the 114’s 4-inch bore.
The difference in cylinder stroke, however, is a bit less microscopic and a bit more significant between the two Milwaukee-Eight V-Twin engines.
The 107’s stroke measures 4.375 inches from top to bottom, which is 0.125 inches or 3.175 mm shorter than the 114’s stroke at 4.5 inches.
But regardless of the differences, both the Milwaukee-Eight 107 and 114 are considered “undersquare” engines due to having a longer stroke and a smaller bore.
ESPFI System (Electronic Sequential Port Fuel Injection)
Amid the differences between the 107 and the 114, there is one similarity that these two Milwaukee-Eight engines have with each other, and that is the inclusion of Harley’s own ESPFI system.
The ESPFI (Electronic Sequential Port Fuel Injection) is Harley-Davidson’s fuel system technology that is able to control both the spark timing and fuel flow inside the engine.
Harley’s ESPFI system has been around for a while now, as you can even find it in older 2000s models that didn’t have the Milwaukee-Eight yet.
The ESFI system has three main processes to monitor the timing and fuel flow, namely the “Open Loop”, “Speed/Density”, and “Sequential Port Fuel Injection”.
These three processes utilize many electronic components such as the ECM (your bike’s computer), different sensors, and more.
So whether you opt for the 107 or the 114, your Harley’s fuel system will already come equipped with its own ESPFI that’s keeping your engine’s mix of fuel and spark in check around the clock.
A Full Comparison Overview of Milwaukee-Eight 107 vs 114
In this section, we’ll be giving you an overview of the differences (or similarities) between the 107 and 114’s features, performance, acceleration, engine specs, temperature control, and sound.
In addition, we’ll even be comparing both Milwaukee-Eight engines to their predecessor, the “Twin Cam”.
New Features
When Harley-Davidson first released the Milwaukee-Eight 107 and 114 back in 2016, the two engines already came with lots of additional features that helped them gain an edge over the previous-gen Twin Cam engine.
Both the Milwaukee-Eight 107 and 114 feature more efficient cooling thanks to a twin-cooled (air-cooled and oil-cooled) system as well as the exhaust pipes being relocated further away.
In addition to a better cooling system, the Milwaukee-Eight engine also includes the following features and improvements versus the Harley Twin Cam.
Harley-Davidson Milwaukee-Eight New Features:
- All-new 45-degree “Big Twin” engine that still maintains the rich history of Harley’s earlier engines
- 4 valves in each cylinder for a total of 8
- Powertrain noise has been reduced
- A slimmer and more low-profile engine design
- Idle is set at a lower 850 RPM from the previous 1,000 RPM
- Reduced air intake noise and more efficient airflow
- Equipped with an internal counterbalancer that reduces vibrations during idle by 75%
- New assist and slip clutch decreases clutch effort by 7%
- Improved cooling efficiency and relocated exhaust system
Improved Performance
There is no doubt that Harley went big when it decided to retire the Twin Cam to give way to the Milwaukee-Eight, especially performance-wise.
Despite being the smallest of the Milwaukee-Eight engines, the 107 already packs a whole 111.4 ft-lbs of torque, which is already significantly better compared to the Twin Cam 103’s 100 ft-lbs.
Opting for the 114 will obviously give you even more torque at about 124 ft-lbs, resulting in a smooth yet responsive delivery of power even at lower RPMs.
Let’s also talk about how the new engines affect cornering performance, as we can also see an improvement over the Twin Cam in terms of lean angle, but then again, this also depends on the exact engine and bike model.
For instance, the 107’s lean angles are listed at 32° (left) and 31° (right), while the Twin Cam 103B only allows a lean angle of 23.4° on either side when fitted on a Harley Softail Breakout.
Better Acceleration
With better performance specs naturally come better acceleration (assuming you keep the weight the same), but there are subtle differences between how the 107 accelerates compared to the 114.
Even though it’s a little bit down on power and torque, the 107 is regarded as the more responsive of the two engines when twisting the throttle at low speeds.
This is thanks to the 107’s slightly shorter stroke compared to the 114, enabling it to have a more “snappy” and somewhat more aggressive initial acceleration.
However, once the road really opens up, this is where the 114’s extra punch in torque shines a bit more on the top end with its linear acceleration. Now it’s all just a matter of personal preference.
But whichever Milwaukee-Eight motor you go for, the 9th-gen V-Twin already beats the older Twin Cam when getting up to 70 mph.
You can check out the video below for an acceleration comparison between the Milwaukee-Eight and the Twin Cam.
Engine Specifications
| Harley Milwaukee-Eight 107 | Harley Milwaukee-Eight 114 |
| Engine Type: Radial V-Twin (2-Cylinder) Bore: 3.937 inches (100 mm) Stroke: 4.375 inches (111.1 mm) Displacement: 107 ci (1,750 cc) Compression Ratio: 10.0:1 Fuel System: ESPFI (Electronic Sequential Port Fuel Injection) | Engine Type: Radial V-Twin (2-Cylinder) Bore: 4 inches (101.6 mm) Stroke: 4.5 inches (114.3 mm) Displacement: 114 ci (1,868 cc) Compression Ratio: 10.5:1 Fuel System: ESPFI (Electronic Sequential Port Fuel Injection) |
All of Harley’s Milwaukee-Eight (M8) engines were designed to have Radial V-Twin configurations, and this includes the 107 and the 114.
However, there are differences to be found when closely looking at the cylinders of both engines.
More specifically, the bore and stroke of the 107 are slightly smaller and shorter than that of the 114. Bores for both engines are at 3.937” for the 107 and 4” for the 114, while their strokes measure 4.375” for the 107 and 4.5” for the 114.
Now at this point, you most likely already know where these two engines got their names from. But just in case you don’t, they are named as such due to their engine displacement, which is 107 cubic inches for the 107 and 114 cubic inches for the 114.
The compression ratio is another thing that the 107 and 114 differ in. The 114 has a slightly higher compression ratio of 10.5:1 compared to the 107’s 10.0:1.
Both the Milwaukee-Eight (M8) 107 and 114 engines make use of Harley-Davidson’s own fuel system called “ESPFI” (Electronic Sequential Port Fuel Injection).
Performance Specifications
| Harley Milwaukee-Eight 107 | Harley Milwaukee-Eight 114 |
| Power: 81 hp (rear wheel)/93 hp (crank) Torque: 111.4 ft-lb @ 3,250 RPM Torque Testing Method: SAE J1349 Left Lean Angle: 32° Right Lean Angle: 31° Fuel Mileage (Combined MPG): 45 mpg | Power: 86 hp (rear wheel)/101 hp (crank) Torque: 124 ft-lb @ 3,250 RPM Torque Testing Method: SAE J1349 Left Lean Angle: 34.3° Right Lean Angle: 33.4° Fuel Mileage (MPG): 43 mpg |
Comparing the performance specs of the M8 107 and 114 engines, we are able to see slight differences in just about every aspect.
While Harley never released official horsepower figures for the Milwaukee-8 series of engines (official torque only), third-party dyno tests reveal that the 114 produces 5 hp more to the rear wheels (86 rwhp) than the 107 (81 rwhp).
This kind of power difference is to nobody’s surprise, and it’s the exact same story for their torque figures at 111.4 ft-lbs and 124 ft-lbs for the 107 and 114, respectively. Both torque figures are measured at 3,250 engine RPM.
When it comes to lean angles, the 114 beats the 107 by a slight margin. The 114 enables lean angles of 34.3 degrees (left) and 33.4 degrees (right), while the 107 can only manage 32 degrees (left) and 31 degrees (right).
As for the fuel economy of both engines, the 107 fares a bit better than the 114 with a combined gas mileage of 45 mpg versus the latter’s 43 mpg.
Higher Horsepower Figures
As we’ve stated earlier, there are no official horsepower figures for any of the Milwaukee-Eight engines, as Harley prefers to primarily advertise torque for their bikes (understandable).
But while Harleys aren’t exactly known for their horsepower figures, the Milwaukee-Eight already shows a pretty decent improvement in power output over the Twin Cam.
The Milwaukee-Eight 107 already makes 81 hp to the rear wheels, a respectable number considering a stock Twin Cam 103 makes about 68 to 75 hp to the rear wheels on average.
Of course, the power output only goes up from here when you start comparing bigger Harley engine variants with each other.
A matchup between the Milwaukee-Eight 114 and the Twin Cam 110 will be a slightly closer competition, as the former’s power output averages around 82 to 90 rwhp while the latter makes about 75 to 90 rwhp, according to data by PowerSportsGuide.
Reduced Vibrations
The last thing that you need while you’re on the saddle of your Harley is too many unwarranted massages down there, but thankfully, the new Milwaukee-Eight engine mitigates this a lot better than the older engines.
Both the Milwaukee-Eight 107 and the 114 V-Twins are fitted with a rubber-mounted internal counterbalancer, resulting in a 75% reduction in primary vibrations while on the go.
The only possible difference that you may feel in terms of vibrations in the 107 and the 114 is that the former has a more instant and raw “kick” when accelerating at low speeds, while the latter may feel a bit more smooth due to its linear torque delivery.
But in general, the Milwaukee-Eight Big Twin was designed to provide a more comfortable and refined ride quality than any of the previous engines, a big plus for any American cruiser.
Better Temperature Management
The Milwaukee-Eight is offered with either a standard (oil-cooled) or a twin-cooled system, which employs a combination of the traditional air-cooled method via the flow of air throughout the system as well as liquid-cooled cylinder heads.
This type of cooling system on the Milwaukee-Eight allows for better heat reduction, thus resulting in better temperature management over the previous-gen engines.
The bigger 114 version exclusively comes in twin-cooled form only, while the 107 can be had in both oil-cooled and twin-cooled variants.
In the table below, you can see which Harley models are fitted with the standard 107, twin-cooled 107, and twin-cooled 114 engines.
| Engine Model | Harley-Davidson Model |
Milwaukee-Eight 107(Oil-Cooled) | Road GlideRoad Glide SpecialStreet GlideStreet Glide SpecialRoad KingElectra GlideFreewheelerUltra Classic |
Twin-CooledMilwaukee-Eight 107 | Road Glide UltraTri Glide UltraUltra LimitedUltra Limited Low |
| Twin-CooledMilwaukee-Eight 114 | CVO LimitedCVO Street Glide |
Aside from the cooling system, another notable change that contributes to better temperature management in the Milwaukee-Eight is the relocation of exhaust components like the catalytic converters.
Harley decided to move the catalytic converters further away from the cabin. This, together with the cooling methods we’ve discussed above, led to an impressive 55.6°C (100°F) reduction in exhaust gas temperature.
Richer Exhaust Sound
The distinct sound of the exhaust is possibly what sets apart a Harley motorcycle the most from every other motorcycle out there.
However, there can also be some differences between each Harley engine’s exhaust note, and in the case of the Milwaukee-Eight Big Twin, it’s regarded as having a “richer” tone to it than older engine models, especially with an aftermarket exhaust.
This richer exhaust sound is achieved by reducing the noise made by mechanical components to enable the exhaust to shine more while still conforming to noise regulations in different markets.
Now, richer doesn’t necessarily mean louder, and we think the video below best demonstrates the sound differences between a stock Milwaukee-Eight and a stock Twin Cam, so go ahead and give it a listen!
As you can hear from the video above, the Milwaukee-Eight 114 (black Harley) idles a bit lower than the Twin Cam 103 (blue/white Harley).
Also, despite both having the same “TBR” exhaust, the Twin Cam has a little bit more raspiness to it, while the Milwaukee-Eight has a deeper rumble.
As for which actually sounds better, it can be pretty subjective, which is why we’ll leave it up to you to decide.
Milwaukee-Eight 107 vs 114 – Which one to prefer?
Choosing one Milwaukee-Eight engine over another is all about your own preferences in the overall riding experience.
The 107, while being down on power and torque, is still a very responsive engine even at low revs. It may even feel somewhat more “aggressive” compared to the 114 under load.
The 114 delivers more linear acceleration and doesn’t fall on its face in the higher RPMs as much as the 107 thanks to its bigger torque figures.
However, you will be sacrificing a little bit of fuel economy when opting for the 114, but it really isn’t that much of a change compared to the 107. That’s 45 mpg vs 43 mpg, to be exact.
If you want a sharper lean angle on your Harley, then the 114 is the engine to go for. But again, it’s only a difference of less than 3 degrees between the two.
Needless to say, whichever of the two Milwaukee-Eight Big Twins you choose, you’re still guaranteed to get a refined, great-sounding engine that’s a testament to how Harley engines have improved over the past century.
Frequently Asked Questions
