Fast not furious

Saeed Akhtar is in a stupor as he goes one up on Vin Diesel with a steroid injected Karizma
Photography by Sanjay Raikar


A few decades back, performance enhancement was a term very few bikers in India were familiar with. The racing community was in its nascent stage and most bikers were satisfied with whatever miniscule performance was on offer. But as time progressed, bikers – like all humans – began demanding more from their steeds and started getting familiar with acronyms like NFS, TFATF and thus NOS.

Nitrous oxide systems are still regarded as an arcane art even in most tuning circles. Movies like the Fast and the Furious series, Dhoom and the Need for Speed games franchise have elevated the NOS acronym to something of a cult yet they are also notorious for wrecked powertrains and giant fireballs. First used during World War II in Luftwaffe aircrafts to boost the power output, Nitrous Oxide or N20 is a colourless non-flammable gas with a pleasant, slightly sweet odour and taste. It is popularly known as laughing gas because of the euphoria it induces in humans. Amongst petrolheads too, it induces euphoria but of a slightly different sort. Although it is not flammable in itself, its ability to deliver more oxygen by breaking down at elevated temperatures makes it an excellent catalyst for burning Saudi Arabia’s finest in the fastest possible time. The gas is stored in liquid form and injected either into the intake manifold or right before the cylinder (direct port injection) whereupon its expansion causes more air/fuel mixture to enter the cylinder. By this simple expedient of burning more fuel, very large power gains are possible provided you know how much stress your machine can handle. The increased cylinder pressures caused by nitrous induction have to be harnessed very carefully otherwise you risk blowing off your valves or melting the piston to a molten lump in your enthusiasm. No kidding.

BIKE India has tested NOS kits fitted on the Yamaha Enticer pseudo-cruiser as well as on the screaming Pulsar 180 third gen in the past. This misty morning we ushered in Diwali with the best firecracker we could lay our hands on – a modified Hero Honda Karizma with NOS and a reworked, longer gearing. The blue Karizma featured here is fitted with a 300ml nitrous oxide can that is sufficient to propel the 223cc bike forward for 15 short bursts. Harish Chellani, the owner, importer and installer of the NOS kit, will happily supply you bigger containers for more bursts if you don’t fancy visiting the refill shop too often. Speaking of refills, a 300ml refill will cost you only 150 bucks – a fair bargain considering the power that’s on offer. Harish has found a convenient location for the cylinder in the sari guard, from where a silver coated pipe carries the gas to the inlet manifold. Call it direct injection if you will. A toggle switch, resembling the ones used in old spy movies, that controls the NOX induction is mounted inside the fairing. With it, in the on position, the horn switch ditches its usual duty as a traffic shredder and assumes the role of a catapult. Harish hasn’t fiddled with the carb yet but he has two jets of different sizes for varying amounts of nitrous boost, depending on your craving. The smaller one was on the bike and the bigger one was, well, in his friend’s pocket. Bugger!

The rules are clear and simple, you can employ nitrous boost in every gear provided the rpm is above 4000 and the throttle is fully wrung to the stop. On my first run on the expressway, I gingerly pressed the horn button while in the second gear and braced myself for the kick in the back. Although it didn’t quite qualify as a kick, the tacho needle went berserk and raced up the limiter very fast – too fast for a 223cc bike! Approaching the limiter, the engine roared like it was going to blast its innards out if I persisted anymore. Hmmm. . . . must be time to wind up another gear. A momentary slowing down of pace and it was mayhem again as I pressed the horn button hard enough to snap it off its mounting. No time for glancing down at the speedo or tacho, my eyes were too busy watching out for innocent and beautiful belles with pitchers straying on the tarmac as well as four-legged creatures answering nature’s call right in the middle of NHAI’s crowning glory. If you have not ridden anything on the far side of a Ninja 250 or a RD350, the acceleration even with the smaller jet and longer gearing (14 teeth front/38 teeth rear sprocket a opposed to 13/40 stock sprockets) is astounding. The noise too! Even in higher gears, the bike pulls with such alacrity, that it is very easy to cross sane speeds unless you are also keeping an eye on the speedo. Which frankly, we won’t recommend. Whereas this Karizma (with a reworked gearing) does the 0-60km/h run in 4.77sec sans the laughing gas, it does the same run in 3.87sec flat with it. The 100km/h mark was done and dusted in 10.06sec with NOS. Without it, the bike touches the ton at a relatively slow 13.10sec. Lack of saddle time and horrendous traffic prevented us from taking the top speed estimate, although it must be fairly high up on the stock bike. Sorry.

The downsides of this manic exercise are that it becomes very difficult to resist a dab on the horn button every time you see an open stretch of tarmac. If you are ready to compromise a fair bit on the longevity front for some adrenalin, go right ahead and install it – it’s worth every precious penny. Whether it should be used on public roads is an issue only your heart can decide. However, continuous high revving will eventually take its toll on the bike. A small price to pay, we reckon, considering the excitement that’s on offer.

The NOS cylinder finds a convenient home in the saree guard

The sprocketing has been revised for a higher top speed

Faster acceleration and higher top speed hand in hand, gimme more.'

Bike India Team – who has written posts on Bike India.

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