Royal Enfield's famous single cylinder "thump" is about to be joined by the rumble of a new parallel twin engine. To be fitted to the company's new Interceptor INT 650 and Continental GT 650 models, the new parallel twin has the typical Royal Enfield vintage look coupled with power and torque figures that are a considerable step-up from the company's single cylinder line-up.

The last time a parallel twin was fitted to a Royal Enfield it was on the 1970 Interceptor, and the new 648 cc lump stays true to its style heritage with its air cooling fins and lashings of chrome. The single overhead camshaft, fuel injected design produces 47 bhp (36 kW) and 39 ft-lb (52 Nm). Drive is provided by a six-speed transmission, which is unheard of in a Royal Enfield. The sixth cog is a welcome addition that should provide better fuel economy and make long highway journeys a lot more comfortable – in other words, it shouldn't feel like the engine is about to explode as per some existing models.

Royal Enfield also worked a lot on the acoustics of the new engine to ensure that the exhaust note is just as memorable as the single-cylinder unit that loyal fans have become so accustomed to. The new twin has a 270-degree one-piece forged crank with a balance shaft and, along with the twin mufflers, should provide a sweet V-Twin rumble. In what is becoming a well trodden route, the aim is to deliver the beautiful exhaust note of a V-Twin while maintaining the compact dimensions that a parallel engine configuration provides.

In fact, looking at the engine side-on, you could be forgiven for thinking it was just a typical Royal Enfield single cylinder. It's not until you notice the second exhaust header that you realize something is different.

The new engine will power the new Interceptor INT 650 and Continental GT 650 models unveiled at the EICMA Motorcycle Show this week.

Resurrecting the Interceptor

The Interceptor INT 650 is a modern interpretation of the bike built between 1960 and 1970. It retains some of the styling of the old chugger with its teardrop shaped fuel tank, wide bars, sculpted seat, twin shock absorbers, 18-inch wire spoked wheels as well as the period appropriate, twin upswept exhausts.

The bike's all new steel cradle frame has been developed with the help of British motorcycle tuning house, Harris Performance. Other modern features include the fitment of Pirelli tires front and rear as well as disc brakes with ABS.

Overall the Interceptor INT 650 looks extremely stylish, especially finished off in Crush Orange.

Revamping the Continental GT

Royal Enfield is also fitting the new engine to the redesigned Continental GT 650. The new Continental shares much of its styling with the original 535 cc remaster from 2013, but the engine, frame and driveline are shared with the Interceptor INT 650.

The subtle styling differences include a small oil cooler on the front, while the remote reservoirs for the rear shock absorbers have been moved to the top of the bike rather than being at the bottom of the shock.

Royal Enfield has not stated whether this Continental will replace the current model, but they will most likely be sold alongside each other.

Official pricing is yet to be announced for either bike, but we expect them to go for slightly more than the current crop of Enfield's at around $8-10K.

So how does the new parallel twin it sound? Check out the development video for the new Royal Enfield Interceptor and Continental below.

Source: Royal Enfield

View gallery - 14 images