Turning a Hero Honda Splendor Into an EV: A Practical Conversion Study

My 2004 Hero Honda Splendor in all its glory.

Summary

I spent the past few weeks exploring whether you can take an old 2004 Hero Honda Splendor, the classic Indian commuter bike, and turn it into a fully electric motorcycle using parts you can actually buy today. No fancy lab, no custom manufacturing, just a practical, realistic conversion.

The study breaks down how the electric setup would fit, what performance you could expect, how much it would cost, and whether the whole idea even makes sense for everyday city riding. Spoiler: it looks surprisingly doable, way cheaper to run than petrol, and way better in traffic.

This isn’t a build diary yet, just the concept, the numbers, and the plan. The hands-on project comes next.

Abstract

This study explores the design of an electric conversion for a 2004 Hero Honda Splendor, originally powered by a 97.2 cc air-cooled petrol engine. The project examines how replacing the internal combustion system with an electric drivetrain could improve both efficiency and thermal performance in city traffic. The proposed setup uses a 3 kW brushless DC hub motor (48 V, ~90 Nm peak torque) paired with a 48 V, 40 Ah lithium-ion battery offering roughly 1.92 kWh of energy. A 60A BLDC controller with regenerative braking manages power delivery. The design estimates a range of around 65 km per charge and a top speed close to 80 km/h, with an overall conversion cost between ₹65,000 and ₹75,000. Beyond performance, the retrofit aims to reduce heat buildup, enhance torque in stop-start conditions, and cut daily running costs compared to a petrol counterpart. At the same time, the study acknowledges technical, regulatory, and economic barriers that must be resolved for large-scale adoption. Overall, it positions electric retrofitting as a practical and sustainable path toward cleaner, more efficient two-wheel mobility in India’s cities.

Introduction

Urban India continues to wrestle with traffic congestion, noise, and polluting two-wheelers. Motorcycles like the 2004 Hero Honda Splendor have been city staples for decades, as they’re famous for reliability but limited by the inefficiency of their small air-cooled engines. These engines waste much of their energy as heat, friction, and idle loss, especially in slow-moving traffic. With electric drivetrain components now widely available, there’s a growing opportunity to retrofit existing motorcycles instead of replacing them entirely.

This study explores how an air-cooled petrol motorcycle can be converted into an electric one using commercially available parts. The key question is how such a conversion could improve both energy efficiency and heat management in urban conditions. Rather than physically building a prototype, the focus is on creating a realistic conceptual design and assessing its technical and economic feasibility.

The motivation behind this work stems from three main factors. First, India’s enormous two-wheeler fleet plays a major role in both emissions and urban heat. Second, electric motors are inherently more efficient and require far less maintenance. And third, converting existing motorcycles offers an affordable path to sustainability as it lowers environmental impact without forcing full replacement. Ultimately, this study aims to show that a well-designed retrofit can extend the life of familiar vehicles while delivering clear performance and efficiency gains.

Problem Statement

The 2004 Splendor’s 97.2 cc air-cooled engine is extremely reliable, but it’s far from efficient. In heavy traffic, air-cooled engines can’t maintain a steady temperature because there’s not enough airflow to keep them cool. As heat builds up, the efficiency drops, and the engine starts working harder than it should. The result? Lower mileage, higher emissions, and more maintenance. 

Stop-and-go traffic only makes things worse. Every time the motorcycle idles or accelerates, it burns fuel without actually going anywhere. A huge portion of the fuel’s energy ends up as waste heat pouring out of the exhaust or radiating from the cylinder fins. Small petrol engines like this rarely top 25 % efficiency, while electric motors can hit 80 % or more under normal conditions. That gap comes not just from better motor efficiency, but also from avoiding clutch losses, gear shifts, and fuel use while idling.

For Indian riders, the problem scales up fast. Hot weather, long commutes, and chaotic city traffic combine to push the Splendor’s engine to its limits. Swapping it for an electric powertrain would fix many of these issues by cutting out idle fuel waste and minimizing heat buildup, making the motorcycle far more suited to urban life.

Literature Review

Researchers and engineers have been exploring the idea of electric motorcycles for more than a decade. Chen and his team (2019) experimented with a hybrid setup that paired an electric motor with a traditional internal combustion engine using a power-mode switching system. Their tests showed lower emissions and better fuel economy, proving that electric assist can make a real difference. Across Southeast Asia, small retrofit projects have gone a step further, converting commuter motorcycles to electric power and getting 50–70 km of range with only modest costs.

Other studies, like those published in the AIP Conference Proceedings (Rachman & Priyono, 2024), have shown that swapping out a motorcycle’s ICE drivetrain for an electric hub motor can cut running costs drastically, as long as the weight balance and components are properly matched. Policy research from the International Council on Clean Transportation (Singh & Bandivadekar, 2021) supports this, as it claims retrofitting as one of the most affordable paths to decarbonizing India’s massive two-wheeler market.

Still, there are real challenges. Certification standards for retrofitted vehicles are unreliable. Batteries wear out over time, charging networks are limited (although increasingly popular), and fitting electric systems into existing frames isn’t necessarily straightforward. Even so, both researchers and industry experts are starting to see retrofitting as the bridge between today’s petrol motorcycles and tomorrow’s fully electric future. This study builds on that momentum by focusing on one of India’s most recognized and popular platforms, the Hero Honda Splendor.

Methodology and Design Approach

The conversion follows a theoretical retrofit, rather than a hands-on prototype. The goal was to explore if a 48 V electric powertrain could match or outperform the Splendor’s original engine while staying realistic in cost, weight, and space.

The process started with a deep look at the Splendor’s frame and structure, such as the wheelbase, ground clearance, engine mounts, and the space under the seat. These details helped identify where the new electric components could fit. Removing the air-cooled engine, gearbox, and fuel tank by first draining the fuel and exhaust would free about 25 kilograms and open up enough room for the new system.

A 3 kW BLDC hub motor was chosen for the rear wheel, which removes the need for a chain drive altogether, hence removing extra weight and moving parts. The lithium-ion battery would sit in the old fuel tank area with space under the seat for extra cells if required, while a 60 A controller mounted nearby would manage power delivery and enable regenerative braking. The goal was to keep the motorcycle’s balance and handling close to stock while maintaining good electrical safety and temperature control.

Heat management was a big consideration throughout. Unlike the petrol engine that needed airflow to cool it, the electric system runs cooler and doesn’t need active cooling. Only the battery needs light ventilation. The overall plan is straightforward but practical: remove the old parts, fit the electric components, do the wiring, and test the system for both electrical and mechanical safety.

Component Selection and Design Parameters

Choosing the right components meant finding a balance between performance, cost, and how the parts would physically fit on the motorcycle. The 3 kW BLDC hub motor was picked because it provides enough power for daily commuting, as seen in many electric scooters on the Indian market, while keeping the setup simple and reliable. With around 90 Nm of peak torque, it delivers strong acceleration from a stop, even with a single-speed setup. A 48 V system was selected for safety, efficiency, and compatibility with parts that are easy to find locally.

The 48 V, 40 Ah lithium-ion battery stores about 1.92 kWh of energy, giving the motorcycle an estimated range of around 65 km in normal city traffic without making it too heavy. The 60 A controller works in sync with the motor’s current demands and supports regenerative braking to recover some energy during slowing and braking.

The total curb weight goes up by roughly 25 kilograms because of the new motor and battery, but the overall weight still falls within the normal range for commuter motorcycles. The total conversion cost is expected to be between ₹65,000 and ₹75,000, covering the motor, controller, battery pack, wiring, mounts, and labour. All components are commercially available in India, meaning the entire setup can be built using locally sourced parts without relying on expensive imports.

Calculations and Analysis

To estimate performance, basic energy and cost calculations were made. The battery stores 1.92 kWh of energy, and assuming an overall drivetrain efficiency of 85%, the usable energy becomes 1.63 kWh. With an average consumption rate of 25 Wh/km, the range can be calculated as

which suggests the motorcycle could travel about 65 km on a full charge.

The motor’s rated power of 3 kW at 48 V gives a current draw of 

which matches the controller’s 60 A limit. Considering the aerodynamic drag and rolling resistance typical of a light commuter motorcycle, this setup would likely allow a top speed of around 80 km/h.

Cost comparisons make the benefits clearer. The stock Splendor averages about 80 km per litre of petrol. With fuel priced near ₹100 per litre, the running cost is roughly ₹1.25 per km. For the electric version, assuming electricity costs ₹8 per kWh, each kilometre consumes 0.025 kWh, which equals ₹0.20 per km. The savings per kilometre at ₹1.05 represent about an 84% reduction in running costs. Over a year of 40 km daily commuting, this could save roughly ₹18,500 in fuel, hence representing a significant decrease in running costs. With the same number of kilometers per day, it would take between 3.5 to a little over 4 years to recover the conversion cost. 

Performance-wise, the difference in torque is significant. The original petrol engine produces about 8 Nm, while the electric motor generates up to 90 Nm, delivered instantly. This translates to quicker acceleration in city traffic and smoother low-speed control. With no idle fuel burn or exhaust heat, the electric system also runs cooler and more efficiently, making it far better suited to stop-and-go urban conditions, especially the highly populated metropolises in India.

Results and Discussion

The design analysis suggests that converting the Hero Honda Splendor into an electric motorcycle is both technically achievable and financially practical. The retrofit shows clear advantages like better efficiency, lower running costs, and improved cooling systems. With a comparable top speed and a range that fits most daily commutes, the converted motorcycle could handle urban travel with little to no sacrifice in performance or usability.

This research also shows that giving existing motorcycles a second life as electric vehicles can be a smart, realistic step toward wider electric adoption. It helps cut down on manufacturing and automotive waste, makes use of familiar and proven platforms, and allows riders to shift to cleaner mobility without waiting for new models to enter the market.

That said, the results need to be interpreted carefully. The calculations assume ideal conditions like steady efficiency and effective battery performance. In reality, though, factors like terrain, traffic, temperature, rider weight, and riding style would all impact performance. Over time, battery ageing could reduce range, and the way components are fitted could change how the motorcycle handles.

There are also important regulatory and technical considerations. Retrofitted motorcycles must comply with Indian safety and certification standards from agencies like ARAI. Each design would need testing for electrical safety and frame integrity before being approved for road use. These are not deal-breakers, but they represent that inspection is needed as retrofitting becomes more common.

Challenges and Future Work

While the results look encouraging, several parts of the conversion still need closer study. Battery management is especially important in India’s heat. Lithium-ion batteries tend to degrade faster at high temperatures, so including proper ventilation or a simple cooling setup would be necessary to maintain performance over time.

Another key issue is regulation. India’s retrofit approval process is still developing, and most converted motorcycles have to go through individual inspections. For large-scale adoption, the certification process would need to become faster and more consistent.

The long-term cost should also factor in battery replacement after three to five years of use. The initial investment may pay off quickly, but the overall economics will depend on how battery prices and charging networks change in the coming years.

The motorcycle’s handling and structure also need more analysis. The added weight and changed weight distribution could affect balance, suspension, and frame stress. Running simulations such as finite element analysis would help check for durability and safety before any road testing.

Furthermore, exploration of electric-powered manual transmissions could be used to implement in EV-motorcycle conversions. Although they require a more complex conversion, these geared electric motorcycles would help with power conservation as well as more controlled torque, especially under heavier loads. 

Future studies could build on this work by testing a physical prototype and recording real energy use, ride comfort, and braking behaviour. Experiments with higher-voltage systems, modular batteries, or lighter enclosures could further improve range and performance. These steps would help turn the design from a concept into something ready for real production.

Conclusion

This study shows that converting a 2004 Hero Honda Splendor into an electric motorcycle using a 3 kW BLDC hub motor, a 48 V 40 Ah battery, and a 60 A controller is both technically possible and financially reasonable. The conversion could offer a range of about 65 km, a top speed close to 80 km/h, and nearly 88% lower running costs per kilometre. Along with these performance gains, the retrofit eliminates the Splendor’s heat losses, idle fuel use, and exhaust emissions.

Although the design is theoretical, it demonstrates how electric conversions could extend the lifespan of India’s large two-wheeler fleet while helping reduce pollution in cities. The real challenge lies in improving battery safety, streamlining certification, and managing long-term costs. Once these areas are addressed, conversions like this could become a realistic option for affordable, low-emission transport.

Electric retrofitting does not replace the need for new EV manufacturing but works alongside it, bridging older machines with newer technology. For young engineers and anyone interested in sustainable design, projects like this show how simple, well-thought-out engineering can make a genuine difference in daily transportation.

References

Chen, P.-T., Shen, D.-J., Yang, C.-J., & Huang, K. D. (2019). Development of a hybrid electric motorcycle that achieves energy efficiency and controllability via an inverse differential gear and power mode switching control. Applied Sciences, 9(9), 1787.

Rachman, A., & Priyono, B. (2024). Techno-economic analysis of converting an ICE motorcycle to an electric motorcycle in Indonesia. AIP Conference Proceedings, 2859(1), 020001.

Singh, A., & Bandivadekar, A. (2021). Fuel consumption reduction technologies for the two-wheeler fleet in India. International Council on Clean Transportation.

Times of India. (2022, June 1). EV retrofitting for two- and three-wheelers: cost of conversion and scope. The Times of India.

JMK Research. (2022, December 22). Retrofitting: a viable solution to limit vehicular emissions in India.