SPY SHOTS: New Harley-Davidson engine caught during independent bench tests

There’s been rumours about new Harley-Davidson engines for a while, and it looks like our friends at Revzilla in the States have got the first look at the new 107 cubic inch motor, dubbed the Milwaukee Eight.

According to Revzilla, displacement of 107 cubic inches is confirmed, with a 114-inch and possibly also a 131-inch variant following. In 2017 the engine will be used for Harley’s touring bikes, but by 2018 the new engine might power all the big twin models.

Revzilla’s source is from an independent test facility, and has a lot of info about the technical detail. Here are the highlights:

• The new engines are a single-cam design, with four-valve heads.
• The cam is chain-driven, and the valves are operated by a forked rocker.
• The engines have the heads both oil- and water-cooled. Oil feeds from the rear rocker box up to the front.
• Redline is potentially higher than a Twin Cam, but capped at 6,000rpm.
• Apparently the feel and the sound are both different from a traditional Harley.
• There are two different size mufflers, due to the emissions equipment.
• The header is said to be far easier to remove than the outgoing Twin Cam.
• The air cleaner is a high temp/strength type of plastic.
• Inside the heads, valves are operated by forked rockers, and there are locknut style valve adjusters up top.
• The clutch and the compensator sprocket design have also undergone revision.

At the moment we don’t know how the new engine fits in with the Euro 4 emissions regulations, but if all the big twins are going this way it’s probably safe to assume that the engine will be emissions-friendly enough to land in the European market pretty soon after it’s been officially launched in the US.