Harley-Davidson’s old ‘Twin Cam’ engine will disappear from the model range next year as all the firm’s Dyna and Softail models follow in the footsteps of its Touring and Trike ranges and adopt the new Milwaukee-Eight V-twin.
The move means that all Harley’s ‘big’ bikes will be using the new Milwaukee-Eight from 2018, sounding the death knell for the Twin Cam motor that’s been Harley’s mainstay since 1999.
Despite its retro appearance, with cooling fins and Harley’s tradition 45-degree V-angle, the Milwaukee-Eight is a high-tech design. Most importantly it has four valves per cylinder cleverly operated by a single block-mounted camshaft and pushrods. Although often derided by DOHC-obsessed riders used to European or Japanese bikes, the pushrod setup makes for much smaller cylinder heads and an engine that’s more compact overall. That’s useful when, as with the Milwaukee-Eight, the motor’s capacity is nearing the 2-litre mark.
Other notable Milwaukee-Eight features are twin sparkplugs for each cylinder and the fact that Harley makes both versions with both oil-cooled and water-cooled cylinder heads. The smallest version of the engine is the 1746cc ‘107’ (107cu in). There’s also the ‘114’ (114cu in) version, which is 1868cc in metric terms, and in 2018 some of Harley’s top-of-the-range CVO models will get an even larger ‘117’ (117cu in) version, which equates to 1923cc.
Peak power figures for the engines are lower than you might expect – ranging from around 92hp for the smallest, oil-cooled 107 to about 101hp for the 114 version with water-cooled heads. The new 117 will make about 105hp. But those numbers don’t tell the whole story – Harley engines are about torque, and even the smallest Milwaukee-Eight makes a stomping 110lb-ft at just 3250rpm. The 114 makes up to 122lb-ft at the same speed, and the 117 should be capable of around 130lb-ft.
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Which bikes will get these engines next year?
Documents filed a the EPA – the United States Environmental Protection Agency – reveal the full line of bikes that will get the Milwaukee-Eight engine next year.
As well as continuing in the Touring and Trike ranges, it spreads to the Dyna and Softail lines.
The full range of Dyna and Softail bikes getting the Milwaukee-Eight is as follows:
Breakout
Breakout S
Breakout S Anniversary
Softail Deluxe
Fat Boy
Fat Boy S
Fat Boy S Anniversary V
Fat Boy S Anniversary X
Heritage Softail Classic
Heritage Softail Classic S
Heritage Softail Classic S Anniversary
Low Rider
Softail Slim
Street Bob
Fat Bob
Fat Bob 114
You’ll note that the Breakout, Fat Boy and Heritage Softail Classic all get ‘S’ versions. Currently Harley’s blacked-out ‘S-Series’ bikes already includes the Fat Boy S, alongside a Softail Slim S and Low Rider S. It appears the latter two are being replaced by the Breakout and Heritage Classic for 2018.
The abundance of ‘Anniversary’ models is also clear. That’s because 2018 is Harley’s 115th birthday year. While we don’t have details of what will distinguish the Anniversary models, it’s likely to be paint and trim rather than any major mechanical changes. Notably the Fat Boy S gets two Anniversary editions – the ‘V’ and ‘X’ – at the moment there’s no indication of what will distinguish the two.
The EPA documents don’t reveal exactly which models get which engine size, although its name clearly shows that the Fat Bob 114 will use the larger Milwaukee Eight. It’s likely that the ‘S’ models will use the 114 while the base version of each bike uses the 107. As most of these bikes are naked, they’re likely to use the oil-cooled cylinder heads rather than the ‘Twin-Cooled’ water-cooled heads used on some of the part-faired Touring models.
The models that appear to be getting the new 117 version of the Milwaukee Eight are the new CVO Ultra Limited and CVO Ultra Limited Anniversary.
Harley-Davidson usually reveals its new models in the last week of August each year, so we shouldn’t have long to wait until we discover the full extent of the changes. But for anyone interested in one of the firm’s mainstay big twin models, 2018 may well prove to be a landmark year.
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Topic: Big Twin cams maybe gone 2018 (Read 8736 times)