India's First & Only Fuel Injected 2 Stroke Engine

Recently my second book was published, 23 years of experience, 3 years of writing, all the hard work gives a deep sense of fulfilment. GOOD WRITING REQUIRES GOOD READING. That is something I have been doing since my younger days. I had regular subscriptions of various magazines, Auto, Business and Sports as those were my primary subjects of interest (automobiles, stocks and sports – in that order) at the time.

In 1996, one of the articles I came across was about the Kawasaki Ninja. Not only the motor bike looked very stylish, its prominent feature was the 1000cc fuel injected engine. It was much advanced technology for the Indian market, as at that stage, most of the motor bikes available here used a carburettor. The carb, as it was also referred to, relied on the simple principle of pressure differential to push the requisite amount of air-fuel mixture into the cylinder. It was quite easy to maintain and spare parts were available almost everywhere. With the introduction of stringent emission regulations in mid 90s, all carb equipped two stroke engines became non-compliant due to the imprecise manner of combustion.  Consequently, fuel injection became a necessity instead of being only a pricey alternative. It was then I got inspired by the idea of modifying an existing two stroke motor bike with a fuel injected system. I discussed the idea with a friend – Devendra Damle, who had a background in electronics. He immediately agreed and we started working on a project plan.

We needed a suitable motor bike to start with. Most of the young generation in that period was fascinated by the unique “vroom” sound of the two stroke engine of Yamaha RX100. It represented everything you wanted to be as a youngster – bold and invigorating.  However, Yamaha discontinued that model around 1996. Unfortunately for Yamaha, they were not able to capture public imagination with their subsequent models (RXG, RX135) as much as they did with the RX100.   So, it was an easy decision when we selected that bike for our project. It also helped that one of our friends – Anand Thombare – actually did own one.

After the “bike borrowing deal” was finalised with Anand, we had to arrange remaining components of the system. Fuel injection systems comprise three main components – fuel injector, fuel pump and an electronic circuit to control the injection timing. That fine control of injection timing is the major point of difference with the carb along with the presence of a fuel pump to generate requisite pressure. The search for those items took us to several junkyards in Pune and Mumbai. The main issue was to find small enough injector and pump as most of the injectors available in the market were meant for bigger size car engines. Somehow, we did manage to find both items that would fit. Subsequently, we also purchased a small switch to control the injection timing and thus began the actual quest for converting a Yamaha RX-100 from two stroke carb to electronic fuel injection.

I lived in a residential apartment block at the time and the backyard of that building became our makeshift workshop. Our first task was to fabricate a suitable mounting bracket for the injector and pump. We were very fortunate to find a welder in the local industrial area who was very willing to help in our project at a discount rate. The switch was mounted to the engine crank at the bottom and finally we attempted to start the engine. There was great joy when the engine did crank eventually. However, it was short lived when the switch got shattered into pieces after few seconds of operation. Debris went flying everywhere – literally and emotionally.

That gave way to our first upgrade to the setup wherein we sourced a non-contact type sensor to control the injection pulses.  Although that worked better, we did end up damaging a few of those sensors due to vibration of the bracket attached to the crank. Eventually we did manage to fabricate a more stable bracket and the sensor was able to survive. A further modification to the electronic circuit meant a more stable injection pulse and an engine that was becoming functional. It was then a matter of packaging the parts on the bike to allow a test ride. A local test ride was successful with some minor variations to the fuel hose and a longer test ride was planned.

With the help of our motley crew of friends such as Anup Kale, Anand & Sandeep Jagtap along with Devendra and myself, we set off on a 30 km ride to Narayanpur (a holy place with winding road). One of our friends had packed the carb in his backpack just in case there was any malfunction in the new system. Apart from a couple of air-locks (that had to happen in heavy traffic), the ride went quite well. Thus, we had realised our dream of converting the Yamaha two stroke engine to a fuel injected version. That was followed by an emissions test (PUC) and those readings indicated big improvement over the original readings taken before the project. There were a few celebrations following that ride. Devendra and I owe this success to that group of friends who constantly encouraged us along the way and volunteered for the test ride even though it was fraught with risk.

The initial “deal” with Anand was to borrow his bike only for couple of weeks. However, that stretched to nearly 4 months mainly due to lack of two key factors – time and financial resources. Both of us had full time jobs and could not stay away for long periods and both of us had made other financial commitments before the project.

Hindsight is always 20/20. It required a lot of energy, perseverance and technical skill to achieve the above outcome. Along with the above three characteristics we had one more in abundance at that time – naivety. Despite the project being successful, we had little idea of how to showcase it to the rest of the world. We made few feeble attempts to discuss it with some influential people, but that never really led to any meaningful outcome. After few months of further inaction, it was simply dumped into the “too hard basket”.

All this not withstanding, the best moment of the project came during an interaction with our friendly welder. Despite having little understanding of the project or electronics or fuel injection, after watching us fiddle with that engine near his workshop one day he said - Aplya gaadi la punn he asla engine lavun dya ki” - translated into plain English means “please retrofit a similar engine to my bike as well”. No magazine article or other praise will ever come close to the emotion he expressed in that request.