Cape Town – Harley-Davidson has just introduced its first all-new V-twin engine in 15 years, in fact only the ninth of its 113 year history. The Milwaukee-Eight is available for 2017 only in its touring range of machines, but will appear in the rest of the Big Twin range in due course.

The new engine was launched in South Africa this week on a two-day, 600km ride through the Southern Cape with a selection of three 2017 model year tourers and a three-wheeled Freewheeler – which is a Street Glide with a trike rear axle and practically non-existent rear suspension, and will not be mentioned further. So confident was Harley-Davidson in the qualities of its new powerplant that it also provided a 2016 Twin Cam-engined Road King for comparison purposes.

Which highlights the fact that the Motor Company is caught in a trap of its own making. Ever since Willie G Davidson put a part number on nostalgia in 1971, each new Harley has to look like it was designed and built in the 1950s, while complying with the latest noise and emissions regulations (in this case Euro 4) and further narrowing the power and refinement gap to the smooth-running Oriental opposition.

So, from five metres away, it’s hard to tell whether you are looking at a 103 Twin Cam or a 107 Milwaukee-Eight, but the differences are in fact fundamental.

To start with, the new engine is Milwaukee’s first street-legal unit with four-valve heads, hence the name. The new double rockers need a lot more space than the old single-valve rockers, so the rocker boxes are much bigger to accommodate them.

Bore is up from 98.4 to 100mm (the stroke is unchanged at 111.1mm) for a 55cc increase in capacity, from 1690 to 1745cc. More importantly, the old hemi heads give way to pentroof combustion chambers, so the pistons don’t have to be domed, the compression ratio can safely be upped from 9.7:1 to 10:1 and throttle body diameter increased five millimetres from 50 to 55mm.

Boxing clever

The result is a significant increase in power, from 60kW at 4000rpm to 69kW at 5000, as measured by the EPA during emissions testing, and torque, from 138 to 150Nm (or 152 in the case of the range-topping Ultra models, which have the added sophistication of liquid-cooled cylinder heads).

Then chief engineer Alex Bozmoski began boxing clever. He fitted a more efficient internal balancer shaft, went back to less complex and quieter running single-cam valvegear, so that he could make the exhaust note louder without freaking out the EPA’s noise meters, and lowered the idle speed from 1000 to 850rpm for a lower-pitched sound at idle.

He fitted a larger, more powerful alternator so the lower idle speed wouldn’t affect battery charging, changed to a flatter, drag racing-style air filter cover to make more room for the rider’s right knee and made the primary drive casing 16mmm narrower to make more room for the rider’s left ankle.

Finally, he tucked the rear exhaust header much closer to the barrel, covered it with a heat-deflecting shield and moved the catalytic convertor further away under the bike, so that the rider’s right ankle would no longer get fried when standing, feet down, at a red robot.

None of which improved the dynamics of the engine, but they made the bikes much nicer to ride.

Bozmoski did the same with the running gear, fitting new ‘big piston’ Showa forks for more accurate steering (and a smoother ride) and maintenance-free conventional rear shocks with remote preload adjustment by a simple handwheel – the previous air-shocks would go flat and have to be reset if left standing for a month or two.

On the road

The extra power and torque were immediately apparent - the new Road King would easily out-drag the older one, no matter who was riding which bike - with strong torque from 1800rpm and smooth power all the way to the rev-limiter, a first for a Harley; they usually run out of steam before they run out of revs.

More subtle differences become apparent further into the ride. The new bike’s clutch is not only lighter, but also more progressive, making smooth, professional-sounding take-offs much easier.

The new bikes idled with a rich burbling sound and noticeably less mechanical thrashing than the 2016 Road King, and ran perceptibly smoother throughout the rev range; Harley claims a 75 percent reduction in vibration, and I’m not arguing.

Their steering was also distinctly more accurate on the very tight corners of the Tradouw pass between Suurbraak and Barrydale in the Southern Cape, the ride seemingly more comfortable and stability on long sweepers noticeably better.

While the ergonomic updates were measured in millimetres – less than 20 of them on either side - none of the newer bikers stretched my left hamstring on a long fast section, while the previous-generation Road King left me limping slightly after 90 minutes at the national speed limit.

The older bike was also the only one that scorched my right calf, when I sitting on it with the bike on its side-stand.

VERDICT

The improvements are incremental rather than dramatic; you really do have to ride them back-to-back to appreciate how much work has gone into the new Milwaukee-Eight engine and the touring models it powers, but even before I had ridden the 2016 model I had formed a perception that the new bikes were both more responsive and more refined than the Harley tourers I’d ridden in the past.

You can buy better, more comfortable touring bikes for less money, but none of them look like they were designed in the 1950s – and for many riders, that’s what’s important.

FACTS

The three models we rode on the Milwaukee-Eight launch were the Road King, the Street Glide and the range-topping Road Glide Ultra. Their specifications are mostly the same, but where they differ, they are quoted in the order just mentioned.

Engine: 1745cc air/oil/liquid-cooled four-stroke V-twin.

Bore x stroke: 100 x 111.1mm.

Compression ratio: 10.0:1.

Valvegear: Pushrod with four overhead valves per cylinder.

Power: 69kW at 5000rpm.

Torque: 150Nm at 3250rpm.

Induction: Electronic Sequential Port Fuel Injection with one 55mm Mikuni throttle body.

Ignition: Digital electronic.

Starting: Electric.

Clutch: Cable-operated multiplate wet clutch.

Transmission: Six-speed constant-mesh gearbox with final drive by toothed belt.

Front Suspension: 49mm Showa conventional cartridge forks.

Rear Suspension: Dual hydraulic shock absorbers remotely adjustable for preload.

Front brakes: Dual 300mm floating discs with Brembo four-pot opposed piston callipers and ABS.

Rear brake: 300mm disc with four-pot Brembo opposed piston calliper and ABS.

Front tyre: MT90-16 / 130/60-19 / 130/80-17 tubeless.

Rear tyre: 180/65 - 16 tubeless.

Wheelbase: 1625mm.

Seat height: 715 / 695 / 735mm.

Kerb weight: 376 / 376 / 425kg.

Fuel tank: 22.7 litres.

Price: R308 000 / R335 000 / R352 000.

Motoring.co.za

Like us on Facebook

Follow us on Twitter

Subscribe to our Newsletter

Follow Dave Abrahams on Twitter @DaveAbrahamsIOL