News Royal Enfield: Unit Construction Engine

Royal Enfield: Unit Construction Engine

Royal Enfield UCE

The new Royal Enfield single-cylinder 500cc unit construction engine (UCE) supported by electronic fuel injection was first debuted as 2009 motorcycle model year.

The UCE replaced the 70-year-old Royal Enfield cast-iron engine, which had the distinction of being in production longer than any other motorcycle engine in history but ceased production in 2008.

The UCE was amongst the most standard engine designs post World War-II era, where the unit construction integrates the casting assembly of the engine, gearbox and clutch. This technology reduces the friction between the tightly-knit movable parts and hence lowers the transmission losses.

Another technology used in the bike is electronic fuel injection (EFI) which replaced the Lean-Burn Mikuni CV Carburetor engine. The EFI better controls the air-fuel mixture ratios at different speeds and riding conditions.

A better cooling alloy cylinder, stronger crankshaft and connecting rod, improved oiling and a host of other features are all part of the improved Royal Enfield UCE engine.

The UCE 500 EFI was originally unveiled at 2008 Motorcycle Shows in Cologne, Germany and Birmingham, England, although it took until a few years for the news units to hit the U.S. market.

The new model is more powerful, technically advanced and more environment friendly. Important to long time RE motorcycle enthusiasts, it also sport an authentic classic look that reflects original British motorcycle styling.

The old cast-iron engine which was heavy, less efficient, more space consuming and wasn’t very efficient either. The new engine produces 27.5 bhp of power and 41.3 Nm of torque at just 4000 rpm.

The lazy nature and the lowly rpm at which the peak rpm is delivered makes for a very commuter friendly experience through slow moving traffic, with the bike pulling with aplomb in low revs and high gears.

The UCE powerplant is mated to a five-speed gearbox. The gearshifts are spongy and relatively trouble free for an RE. It could take time getting used to the power delivery and the gearshifts but once familiarized, this motorcycle engine won’t let you down.

The engine feels substantially refined when compared with its predecessor and transmits just the right amount of vibration to the handlebars. All you need to reach a three-digit speeds is a full twist of the throttle.

As well, with the new UCE, Royal Enfield became the first motorcycle manufacturer in India to produce and sell a U.S. DOT and Euro-III compliant motorcycle.

Engine: Single Cylinder, 4-Stroke, Spark Ignition, Air Cooled, OHV, UCE
Cubic Capacity: 499 cc
Engine Output/Torque: 27.5 BHP / 41.3 Nm @ 4000 rpm
Fuel System: Electronic Fuel Injection (EFI)
Electrical: 12V System
Ignition: Electronic
Transmission: 5-Speed gearbox with left side gear shift

Ron Lieback
Ron Lieback
One of the few moto journalists based on the East Coast, Ron Lieback joined the motorcycle industry as a freelancer in 2007, and is currently Online Editor at Ultimate Motorcycling. He is also the author of "365 to Vision: Modern Writer's Guide (How to Produce More Quality Writing in Less Time).

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