Thursday 17th August 2017

Harley-Davidson Milwaukee-Eight: PH2

A new motor breathes fresh life into Harley's model range

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This year has marked something of a revolution for Harley-Davidson, not that you would really have spotted it unless you are a fan of the brand. So what is this revolution? Within its 2017 model range, Harley has released a brand new engine - the Milwaukee-Eight. So what's the big deal?

Power for the next generation
Amazingly (or not, depending on how cynical you are about Harleys), the Milwaukee-Eight is only the ninth big twin motor that Harley have built in its 114-year history and only its third all-new big twin in 80 years! And it marks something of a revolution for the firm in terms of its construction and technology.

So the big bike is a 1.7-litre...

Developed entirely in-house by HD, the Milwaukee-Eight ticks all the usual Harley boxes with pushrods activating the valves, a 45-degree V-twin layout and big air-cooling fins. But inside the head are not only four valves per cylinder (activated via a new single four-lobe cam), but also a new dual-cooling system. Well, sort of new: a very similar system was used in the XR1200 to help improve its performance as well as the more recent Twin Cam Rushmore series of bikes, but we will brush over that.

Surrounding the area housing the exhaust valves is what Harley is terming a 'strategic cooling' system. By using a four-valve head design instead of the two-valve one, and also adding this cooling system, Harley have managed to make the Milwaukee-Eight run cooler, not only boosting power but also making it pass new emissions laws as it is a cleaner motor. Add to this a totally redesigned gearbox and rest of the motor (which still runs a ride-by-wire system) and Harley are confident this engine will power generations of models for the foreseeable future. And the changes don't stop there.

Cleverly, Harley have designed the Milwaukee-Eight to be as versatile as possible and as well as a water-cooled version (Harley call this twin-cooled so as not to scare off purists), it also comes in a more traditional oil-cooled format, which is identical but flows oil and not water through the cooling system. Add to this a bigger capacity variant for the more exclusive models in the range and it all adds up to a substantial evolution for the brand. But can you actually spot the difference in the ride? PH2 tested a few Milwaukee-Eight machines to see.

... and the really big one is a 1.8!

A game of numbers
The base Milwaukee-Eight motor is the 107, which comes in both water and oil cooled guises. The more traditional Harley models (Street Glides, Road Glides and Road Kings) use the oil-cooled version while the touring models (Ultra and Road Glides) use the twin-cooled version. What's the difference? If you look really closely, the water-cooled models have an extra set of radiators covered by shrouds at the front of the bike, but otherwise both motors look physically identical. And they feel pretty much the same to ride as well.

With any Harley engine it is almost impossible to get a power figure from the firm; instead it quotes torque and the addition of twin-cooling only gives you an extra 2lb ft, producing 112lb ft compared to the air-cooled model's 110lb ft. So why do it? Reason is tourers tend to spend their time loaded up and being worked harder and another big benefit of the new motor is the fact it runs cooler than the old V-twins, reducing the chances of cooked (basted?) thighs. However while the two variants feel the same, the actual motor is certainly a major leap ahead in terms of the riding experience.

While still feeling, and more importantly sounding, like a proper Harley, the Milwaukee-Eight adds a massive amount more refinement to the ride quality. It is considerably smoother than the old Twin Cam engine and has far less annoying vibrations. In fact, Harley claims a 75 per cent reduction in vibes, with the 25 per cent left for a nice dose of character. Add to this a 10 per cent increase in grunt as well as a gearbox action that while still not smooth, is certainly less agricultural than before and it really is a significant step forwards for the company. Far from the clunky and old fashioned riding experience many assume a Harley will deliver, the new Milwaukee-Eight is refined, smooth and has a really wonderful throttle connection.

And to think this goes in a bike!

As someone who dips in and out of riding Harleys it was a certainly a surprise how far it had moved their performance on, and I am sure owners of the current Twin Cam range will be equally as impressed by the new motor. However, the best was yet to come...

Go big to go home
Where the standard Milwaukee-Eight 107 is 1,745cc (that's 107 cubic inches in American talk), if you opt for one of the firm's CVO (Custom Vehicle Operation) models you get a bigger capacity 114 engine boasting a whopping 1,868cc with 121lb ft of torque. You have to pay a pretty hefty premium for this with the CVO Street Glide £31,295 and the CVO Limited £33,245, but the ultimate always costs a premium and the CVO models really are something very special.

As someone who isn't really into the whole Harley scene it takes a lot to really impress me, but I don't mind admitting the CVO Street Glide knocked my socks off. It is an absolutely outstanding bit of kit and the 114 engine is a beauty. As well as being ultra smooth on a constant throttle, when you crack the throttle it changes character, thumping and pulsing as it drives forward with huge amounts of torque. It's a beautifully smooth and refined engine that really suits the luxurious nature of the CVO models perfectly and is noticeably more eager to accelerate than the 107 variant.

Power? Nobody really knows...

Is it worth the extra cost? In pure performance terms probably not, but can you put a monetary value on rolling up on a proper head-turner?

The heart of things to come
In some ways I wish Harley shouted a bit more when it developed new technology, but the firm is always stuck in an odd place trying to appease traditionalists while also looking to the future and adopting modern technology. The Milwaukee-Eight motor is a case in point. It is a radical change for the company and has evolved its model's performance, reliability and feel on another giant step, but Harley almost seems embarrassed to show off too much about it. Which is a shame as I reckon this new motor could well attract a few non-Harley riders into the brand, especially ones that are being tempted to try an unashamedly modern cruiser such as the latest breed of Indians. Come on Harley, be proud of what you have built - it's a great motor.

[V8 FOU]

Basic architecture of the engine is similar to the TC88.
Very, very deep finning which not only helps cooling, but can reduce mechanical noise.
Very interesting development.