Royal Enfield has launched their first-ever parallel-twin engine powered Interceptor and the Continental GT 650. Both the motorcycles carry an extremely impressive price tag, which has attracted a lot of youths. However, with the all-new bikes, Royal Enfield has used an all-new twin-cylinder engine, which changes the whole characteristics of the Royal Enfield bikes.
Known for their signature thump and popular in the market for the same exhaust note, the all-new 650 Twins do not offer the same signature thump. The above video published by DCV is a proof of the stark difference between the exhaust note of single-cylinder powered Royal Enfield motorcycles and the exhaust note of the all-new parallel-twin engine.
The differences between the exhaust note are because of the way engines are designed. The single-cylinder 350cc and 500cc engines of the Royal Enfield have long strokes compared to the newly launched 650cc engine. Long strokes are inversely proportionate to the average piston time of the engine. Which means the piston takes a longer travel inside the sleeve and it takes more time to complete the cycle.
It translates into a longer time difference between each blast inside the combustion chamber. The time difference between each cycle gives more time to the exhaust gases to escape and each thump can be heard loud and clear individually. This gives the signature thump to the single-cylinder Royal Enfield motorcycles. While long stroke engines are not good to extract power, it sure very torque-rich.
The Royal Enfield 650cc engine has a relatively shorter stroke. There are twin pistons operating inside because it is a parallel-twin engine and each piston has a stroke length of 67.8mm, which is much lower than the 90mm stroke of both the 350cc and the 500cc Royal Enfield engines. The shorter stroke means that the piston has to travel less, which ensures quicker combustion cycles. The average speed of pistons in a smaller stroke engine is much higher, which creates a different sound altogether. Now, there are two cylinders in the 650 twins, which are working alternatively to move the crank. It creates a unique sound, which sounds like rumble than the thump.
It should also be noted that the shorter stroke engines can reach higher RPMs when compared to the longer stroke engines. The Royal Enfield 350cc engine produces the maximum power of 19.8 Bhp at 5,250 rpm and a peak torque of 28 Nm at 4,000 rpm. The 500cc engine produces a maximum of 27.2 Bhp at 5,250 rpm and 41.3 Nm at 4,000 rpm. The all-new parallel-twin engine can rev much higher and churns out its maximum power at a much higher power brand. The new 650cc engine produces a maximum of 47 Bhp at 7,100 rpm and a peak torque of 52 Nm at 5,250 rpm.
Yes, the all-new Royal Enfield has lost the charm of its signature thump but it sure is attractive enough for the enthusiasts and Royal Enfield lovers, especially with the price tag it comes with.