Bajaj Discover 125 ST Insight

This may not be the first article on 500k Motors featuring an economical bike. While I wouldn’t like to place Bajaj Discover 125 ST into the cast of purely economical bikes. Discover series of motorbikes have been better known for their fuel economy and value for money, while Bajaj thoughtfully integrated the components of a sports bike into the one with better fuel economy [ owing to their lighter kerb weights and DTSi technology ] to give out a masterpiece.

Firstly we move on to specifications of Discover 125 ST before going on to detailed review.


Bajaj Discover 125 ST engine specifications

  • Type: 4-valve DTSi air cooled
  • Size: 124.6 cc
  • Max Power: 13 ps @ 9000 rpm
  • Max Torque: 1.1 kgm @ 7000 rpm
  • Top Speed: 110 + km/h [ public review ]
  • Ignition: Digital CDI
  • Carburetor: CV type
  • Transmission: 5 speed constant mesh


Bajaj Discover 125 ST Dimensions and Handling

  • Wheelbase: 1305 mm
  • Ground Clearance: 170 mm
  • Kerb weight: 124.5 kg
  • Fuel Capacity: 10 L
  • Front Suspension: Telescopic Fork with Anti-friction DU Bush
  • Rear Suspension: Nitrox Mono shock with gas canister
  • Brakes: Read Drum, front petal disk brake [ 200 mm ]

[ Credits: Bajaj Auto official page. Take a look here.   ]

Bajaj has kept the discover under an incredible price of 56, 000 [ excluding tax and other fees ] which is quite great. Fuel economy is between 50-70 kmpl depending upon rider. One may think that whats so great in this bike, its just an ordinary bike with Bajaj’s known DTSi technology. We may discuss the three terms that govern the engine of Discover 125 St, i.e. 4-Valve Technology, Digital Twin Spark ignition [ DTSi ] and ignition with digital CDI.

i ) 4 – valve technology: In a typical engine of motorbike [ conventional type ] there is one inlet valve for input of combustion mixture and  one exit valve. If there valves are replaced by 4-valves, i.e. 2 inlet valves and two exit valves, intake and exhaust process of the engine can be made better. There 4-valves come out to be smaller and lighter in weight and aid the easy flow of gases. Bajaj Discover 125 ST has a 4-valve DTSi engine. A 4-valve DTSi engine was patented by Bajaj as worlds first of its kind for Pulsar 135 LS. A 4-valve engine has about 50 % increased area available for combustion as compared to conventional 2-valve engines. This facilitates induction of more quantity of charge (air-fuel mixture) and also evacuation of all burnt gases inside the combustion chamber ensure faster, cleaner & more efficient combustion. The result is increased engine performance-power, throttle response, pick up of all engine speeds. As a consequence a 4-valve engine is lighter, more powerful and efficient. There are no limitations to rpm in an 4-valve engine [ well still one may not cross 11 k rpm mark ].

ii ) DTSi [ Digital Twin spark Ignition ]: DTSi Technology was also firstly introduced by Bajaj Auto, resulting in increased fuel economy of bikes in Discover and Pulsar Segment. In case of single spark engines, the spark created takes time to propagate to other end of combustion chamber and combustion in this case is not quite effective due to slower burning of air fuel mixture, While two spark plugs at either ends of combustion chamber help in efficient combustion. Engine of Discover 125 ST is a DTSi engine ensuring power and fuel economy.

iii ) Digital CDI Ignition: This is micro-controller aided ignition that renders spark characteristics for a given RPM to provide best possible combustion results.

In case of comfort and safety one can get some details from automobile forums as well as official website. Bajaj claims that D.C. headlamp in Discover 125 ST that is directly connected to battery will ensure complete full intensity beam irrespective of engine speeds. This may drain the battery at a greater rate but that can be lived with. Petal front disk brakes are the first ever introduced in a economy class bike, providing better braking through increased area for better cooling.


Bajaj Discover 125 ST  is a best buy for anyone who loves power and yet needs an economical bike. The specifications fit into all requirements like Milage, Power, Comfort, Styling and safety though the price could have been kept a bit low.

Click here for review on Bajaj Pulsar 220.

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