Wednesday, 21 June 2017

Ben's Corner #5: Long strokers from non-RE brands, a distant dream?

If you ask any Royal Enfield owner why he loves his ride, he might reveal two prime reasons: the thump and the torque. Royal Enfield bikes produce a unique thumping sound which no other manufacturer in this world offer. They have good low-end torque (twist force) which helps them move effortlessly even with heavy weight on-board. So, what makes an Enfield different from the rest? Well, it's none other than that massive engine. The brand's highly successful offerings including the Classic and the Thunderbird range sport their flagship, Unit Construction Engine (UCE).

What is an UCE?

In a layman's term, UCE is the aluminium version of the age old cast iron push-rod actuated engine which the Royal Enfields have been sporting since their inception. Developed by AVL of Austria under request from Royal Enfield, UCE is fully made of aluminium. It has a long stroke layout which means the distance travelled by the piston in each combustion cycle is much higher than its diameter. Unlike the engines from other manufacturers, UCE lacks modern technology and is one of the simplest four stroke engines in the world.

Why UCEs are unique?

As the distance travelled by the piston is quite high in an UCE, the piston's inertia is also high leading to the flywheel generating more force in every combustion cycle. This is the prime reason UCEs have more low end torque (twist force). Secondly, as the piston travels a little longer, it accumulates more fuel making every combustion intensive and slow. This is what makes the engine produce the unique thumping sound. The massive displacement of the engine is also another contributor to the phenomenon. Royal Enfield is not only the world's oldest two wheeler manufacturer but also one of the very few long standing highly successful ones in the present times. They are also one of the very few manufacturers still relying on these old school engines.

UCE vs Modern engines

Despite sporting the technologically inferior UCEs, Royal Enfields continue to set the sales chart on fire. The Classic 350 for example sells about 25,000 units every month despite costing a bomb, Rs 1,65,000 (on road). In comparison, Bajaj's latest offering in the segment, Dominar 400 which is directly pitched against the former gets modern technologies like liquid cooling, four valves, radial tyres, full LED headlights, digital instrument cluster, triple spark plugs, etc. But still it's cheaper than the Classic retailing at Rs 1,54,000 (on road, non-ABS). Even after offering more technology and performance, the Dominar hardly sells 1,500 units a month.

Time to follow suit

For a brands as advanced as Bajaj or even Honda, it is as easy as a cup of tea to design an engine very similar to the UCE, a long stroke push rod engine which can thump and exert a massive torque that too without interfering into the patents of either Royal Enfield or the maker of UCE, AVL. Moreover, they have all the room to limit their advanced production processes to make such old school simple designs as the Royal Enfields. Moreover, it can be a massively profitable business even if these brands are able to grab a quarter of the pie of what the Classic 350 manages on a monthly basis.

Still a distant dream?

Though embracing an old technology is not at all a difficult task, brands continue to avoid such strategies. There are many reasons for this. Firstly, an old engine like the UCE is not mechanically sound. It's quite difficult to achieve dynamic balancing in long strokes leading to excessive vibrations cropping up. Such engines are also prone to issues because of the uneven spread of torque. Many Royal Enfield owners have complained of gear wreckage, engine failure, etc. Long strokes' high inertia doesn't allow them to rev beyond a point which is the prime reason why UCE's redline is under 6,000 rpm. So, in general, UCEs are quite unreliable though they ride in a relaxed manner. Secondly, in long strokes, newer emission norms are difficult to adhere to which the reason why Royal Enfield itself developed a SOHC engine for the Himalayan in view of axing the UCE in the near future.

What is the future?

So, as long as the UCE is in production, it might fetch good sales. But it's better not to expect such engines from other manufacturers as the future is moving towards more efficient technologies. At one point of time, Royal Enfield itself will be forced to withdraw the UCE from production. So, until then, this segment remains free to be exploited. If you are an aspiring two wheeler maker, you too can capitalise on the trend.

- S Ben Raja,
Chennai, June 20, 2017.

The above review/analysis is completely the perception of S Ben Raja alone. This does not reflect the views of two or more people or a community. Queries and criticism shall be addressed to the writer only. This author is correspondent for an English daily working on auto beat stories for over a year. Reach him at

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