Tuesday, June 21, 2011

Royal Enfield Thunderbird Twinspark

Design & Engineering
 



A first look, and you would be hardly able to tell the difference between the Twinspark and any other Thunderbird, till you see the engine. It’s a contemporary looking powerplant with an incorporated crankcase and gearbox projected to lessen oil seepage. Every other bit is similar; the round headlamp, double instrument pods, front disc brake, seat and pillion backrest are all the same as the normal Thunderbird’s. A notable visual difference is the shorter muffler that we received on our test bike.
The panels underneath the seat feature a minuscule ‘Twinspark’ sticker, which is the lone sign of this key technical step forward of the bike. Also on either side, just beneath the tank, are round reflectors; a helpful touch when you’re emerging from a side road onto a highway. The fuel tank is sheet-metal, and the overhang welded below it is a blemish, while the fuel tank cap looks dated. The Twinspark does well to offer slow- cam chain adjusters, as compared to the more predictable system provided on most Indian models.

 Drivetrain & Performance


The all-new engine has twin-spark plugs, an automatic decompression facility and unit-construction that the company claims has answered the crisis of oil discharge, a key problem with the old engine. Although a lot does stay alike, other important changes contain a high-flow trichoidal oil pump, hydraulic tappets, an automatic primary chain tensioner and the drive chain assembly shifted to the right side in order to reduce transmission loss. The Twinspark benefits from TCI ignition for a fine spark. You get 2bhp more, for a figure of 19.8bhp, and 2.85kgm of torque, which is a insignificant 0.1kgm more than the older version.
Start it and you instantly notice a smoother feel near idle. The handlebars don’t judder in your hands just yet. Select first gear and as you let the clutch out, it feels a bit improved. A six-plate clutch instead of four makes the difference. As you hasten through the gears, this smoothness unfortunately diminishes however, to be replaced with Royal Enfield characteristic vibrations, Which is where it goes from bad to worse, and it’s apparent that thrashing the engine is not the way to ride this bike.

 Economy


Fuel economy is not a subject of relevance among Royal Enfield bike lovers, who will buy the Thunderbird Twinspark more for its lifestyle value, than economy. For the record, the Twinspark returns 35.7kpl in the city and 36.8kpl on the highway.

 Ride & Handling


The riding arrangement of the Twinspark is classic cruiser fare, and its saddle is a sensibly pleasant place to be on long rides.
The Thunderbird uses known, large, kicked-out forks and an extended single-downtube frame. Its gas-charged dampers at the rear are par for the course for motorcycles in India, but even on their softest setting tend to jump when pushing the bike to its edge. These work best when the bike is overloaded.
The Thunderbird Twinspark is somewhat a burden in city traffic, but a steady bike on the highway thanks to its 19-inch rims. The handlebars do provide ample weight for city riding, but there is no dodging this bike’s rangy wheelbase and heft in the city.


Verdict
RatingRatingRatingRatingRatingRatingRatingRatingRatingRating  5/10
The dreary general quality, the heavy price tag and the out-of-date technology make sure you do not buy this bike by using your head. Yes, the new engine is better and more modern, but then these are changes that should have been made a long time ago.
But looking at the Thunderbird Twinspark as such is missing the point totally. It is a bike you buy with your heart. 
 
 

Royal Enfield Thunderbird Twinspark

Specification

ENGINE


FuelPetrol
InstallationInclined from vertical
TypeAluminium alloy block and head
Bore/stroke70/90mm
Compression ratio8.5: 1
Valve gear2 valves
Power19.8bhp
Torque2.85kgm
Power to weight108.7bhp per tonne
Torque to weight
Specific output57.2bhp per litre

Transmission


Type
Gearbox5 speed, 1-down, 4-up
Ratios/kph per 1000 rpm1st 3.06/7.4
Final drive ratio

Chassis & Body


Construction
Weight
WheelsWire spokes
Tyres3.25 x 19 front, 3.5 x 19inches rear
Spare

Suspension


FrontTelescopic forks
RearGas-shocks, tubular swingarm
 

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