Motorbike Road Racing
How to modify your road bike for circuit racing in India
Kerala-based racer Clutchless explains how a road bike can be modified to make it race ready for the Indian National Motorcycle Racing Championship.
In 2019, Deepak ‘Clutchless’ Vishnu took apart his Hero Impulse and customised it for a ride in the mountains. This was a home project, long before he established UnderGround Tuning, a workshop in Kochi where he builds high performance racing bikes today.
The bike ran on bare minimum, yet had a cruising speed of 90kmph and a high fuel economy of around 62 km/litre. Once in the mountains, Clutchless realised that his bike was performing beyond his expectations. It convinced him that he could make a profession out of bikes and is living that dream today through UnderGround Tuning.
It’s been many years since Clutchless rode at the Indian National Motorcycle Racing Championship. These days, he hopes to get back on the track as part of the Pro Stock (301-400cc) category, which features some of the most powerful bikes in India.
Deepak 'Clutchless' Vishnu
© Jishnu Vaimeethil
“The Super Stock category was removed after the 2020 season, since it was only accessible to factory teams with big budgets or heavily sponsored riders. Today, the Pro Stock category has the most competitive races that feature a full grid of 45 riders,” Clutchless says.
The Federation of Motor Sports Clubs of India (FMSCI), which governs bike racing in the country, issues a handbook of technical regulations at the start of each season, based on which riders must ready their machines. All bikes that are entered in the Stock and Pro Stock category must be made by an Indian manufacturer, using components either manufactured in India or imported by the manufacturer and fitted as original equipment on the vehicle.
Each rider picks up a bike from a manufacturer and customises it for racing. Here, Clutchless highlights the modifications that can be made on a road bike to make it fit for racing in the Pro Stock category at the National Championship.
01
Remove any excess features you don’t need in circuit racing
The first step is to strip the bike of all the non-essential components such as the head lamp, tail lamp, indicators, mirror, horn, helmet hooks and luggage carrier hooks. This will make the bike lighter and therefore faster. Removing other components such as the tachometer, speedometer, instrument, instrument bracket and associated cables is optional. There are a number of components such as the crankshaft and oil pumps that cannot be modified as per the rules. All other modifications, where permitted, must comply with the technical regulations that have been specified.
02
You can’t modify the chassis so pick the right one
Clutchless with a Yamaha Deltabox chassis
© Jishnu Vaimeethil
The chassis is the key to any bike’s build. Clutchless’ preference is a Yamaha Deltabox frame.
“The chassis has to flex under load and when that happens, it gives you feedback that helps understand how the bike is performing. The rider can experience this through the clip-on handlebars and the fork while riding,” he says.
The other preference is the KTM Trellis frame. Clutchless finds it to be on the stiffer side, which limits the feedback received by the rider.
“Once the engine is mounted on the Trellis frame, it gives strength to the triangular lattices. But the downside is that the engine vibrations aren’t felt through the clip-on handlebars, which robs the rider of feedback,” he says.
The main frame of the chassis cannot be altered, which makes it essential to build on an existing bike. Any modification can only be made to the sub frame.
03
Switch to alloy hubs for your tyres
Most tyres made available by Indian manufacturers feature either a U-shaped or a V-shaped profile, which are used for touring and racing, respectively. The National Championship has implemented a rule that any tyre that is used for racing must feature on Stock motorcycles in India and should be accessible to all riders. You could use alloy hubs to make the entire assembly lighter.
“Lighter tyres mean less gyroscopic forces and less unsprung weight, which in turn means better handling. The bike can change direction easily and makes for better braking as well,” Clutchless says.
04
Customize suspension so maximum tyre surface makes contact with the road
Clutchless works on the rear suspension of a bike
© Jishnu Vaimeethil
The most critical part of the build is the suspension, which is based both on the weight of the bike as well as the rider. Clutchless approaches the concept using a well-established theory.
“The idea of changing the suspension is simple – to make more contact between the tyre and the road. The more the contact with the surface, the greater the control that the rider has on it. So one must pick a suspension that ensures maximum contact between the tyre and the road,” Clutchless says.
A bike manufacturer usually uses suspension that caters to a variety of riders and terrain. But on a race track, it is customised for the rider and the surface. Any additional load added to the bike warrants retuning of the suspension.
05
Use fibre glass fairings and seats
Fibre glass body work
© Jishnu Vaimeethil
Most stock bikes come with ABS injection moulded fairings, which are heavy in nature. These make way for replicas made of fibre glass, which are much lighter and reduce the overall weight by almost 3.5kg. The rider and pillion seats are also removed and replaced by a fibre glass single-seater, which makes it lighter by about 3-4kg.
“Carbon fibre is most suited but since it is banned in India, we use fibre glass. Any unsprung weight that is removed will make the bike go faster,” Clutchless says.
06
Use bigger exhaust or twin exhausts
All exhausts are restricted to those made by an Indian manufacturer. In compliance with environmental norms, most bikes come with a catalytic converter that is removed to make it a free flow exhaust.
“Every exhaust is made to tackle a particular rpm because of the resonance that is generated. So if you change the exhaust system, you need to alter the tuning of the bike as well. If I want the bike to generate more torque and power, I need to make the exhaust system bigger. Then again, the length of pipe is limited by the bike’s length, which is why it makes more sense to use twin exhausts,” Clutchless says.