BS4 ENGINE VS BS6 ENGINE – Why BS6 is Better?

To regulate the pollution emitted by cars and two-wheelers, the govt of India has put forth regulations referred to as Bharat Stage Emission Standards (BSES).

The Central government has mandated that each vehicle manufacturers, both two-wheelers and four-wheelers, should manufacture, sell and register only BS6 (BSVI) vehicles from 1 April 2020.

In this article, you’ll study the BS4 vs BS6 engine, major differences, and therefore the performance of the new BS6 engine.

BS6 engine

Technical Difference

First of all, you need to know why BS4 engines are terminated & BS6 engine is introduced in the market. When a motorcycle or car runs lots of harmful gases come out from its exhaust. All these gases harm the environment as well as the human body, So Indian Government time to time brings some new rules known as bs Norms & tell them to all manufacturer company. BS6 Engine produces very less harmful gases compared to BS 4 Engine, here are the limits which are changed in BS 6 Engine,

Two-WheelerCarbon Monoxide (CO)
BS-IV Engine1.970 g/km
BS-VI Engine1.000 g/km
Two-WheelerHydrocarbon (HC)
BS-IV EngineNo Limit
BS-VI Engine0.10 g/km
Two-WheelerNitrogen Oxide (NOx)
BS-IV Engine0.39 g/km
BS-VI Engine0.06 g/km

Engine Operation

In BS 4 Engine you may notice that a maximum of them was in carburetors but in today’s time, Fuel Injection is used mostly in BS6 Engine.

Mechanically & Electrically Operation

In BS4 Engines Carburetor was there, We can manually tune the carburetor from there, Like how much fuel & air we want to send in the Engine. Petcock valve was also there, from where fuel passing can also be controlled. But in BS 6 engine ECU is situated there So everything is automatically controlled there by the ECU unit itself. Bikes coming with BS6 Engine are full of sensors that were not in BS4 Engines, So we can tell that BS6 Engine is more Electrically controlled.

Engine Performance

Fi Engine means in BS6 engines engine performance is also improved, As an example in Pulsar NS 200 in the BS4 Variant engine produces 23.5 ps max power but in the BS6 variant, it produces 24.5 ps max power. But if you tune your BS4 bike properly it can also give you a better performance.

Engine Efficiency

The next important topic is engine efficiency, in easy words Millage, Millage problems are mostly seen in BS4 bikes coming with Carburetors. But we can get better mileage in BS4 bikes also in some cases if we tune the carburetor properly. BS6 Bikes are tuned automatically with the help of sensors so we get better mileage in BS6 Bikes without any issue.

Engine Maintenance

In terms of engine maintenance, BS4 engines are better in my opinion. Servicing cost & the parts price both are cheaper in BS4 motorcycles. In BS6 Engines lots of sensors & actuators are situated there so the parts price & maintenance cost is higher. Another benefit bs4 motorcycles get that they can be serviced by any local mechanic also.

Petrol Quantity

This is also a very important topic, The benefit of the BS4 Bikes with a carburetor which we got that is, the quantity of petrol in the tank doesn’t matter if tanks have petrol the engine will run without any problem but in BS6 with a fi system, we have to always maintain at least 2-3 liters of petrol in the tank for better health of Fi System.


The next important topic is cost, BS6 or the parts of a Carburetor Bikes are cheaper compared to Fuel-Injection, All the components of Fi System & components connected to this are costly, So Carburetor is better in this case. It also affects the price of the motorcycle, Fi Bikes costs more. From IndiaMart you can buy spare parts Online.

FAQ’s on this Topic

  1. What is the difference between the BS4 and BS6 engines?

    Compared to the BS4, the BS6 fuel has less sulphur and NOx. While the content of sulphur in BS4 fuel is 50ppm, it’s five times lower within the BS6 fuel, which is at 10ppm. As for the oxide , the permitted level has been reduced by 70% and 25% for diesel and petrol engines, respectively.

  2. Can we convert BS4 to BS6?

    The emission norm change from BS4 to BS6 is irreversible. On the 1st of April next month new emission norms will see a new sunrise and we‘ll welcome cleaner emission norms.

  3. Does the BS6 engine give more mileage?

    Yes. In layman terms, a BS6-compliant engine are going to be more restricted as compared and can thereby end in a minor drop by power and efficiency. … for instance , the Maruti Suzuki Dzire with the 1.2-liter BS6-compliant petrol engine is claimed to return 21.21 kmpl.


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