Hero Impulse with Karizma engine tested

When we first got wind of the Hero Impulse here at the ZigWheels office, we were naturally all very excited. After so many years, we were getting a motorcycle from an Indian manufacturer that was actually designed to handle more than just smooth tarmac. And even though we were all giggling like schoolgirls after we had our first ride on the bike, there was one unanimous verdict. Everyone thought the bike didn’t sound anything like a dirt bike should and we all wished it had more power to make short work of any terrain the countryside might throw at it. One very obvious question, at least on my mind, was why didn’t they plonk the Karizma engine into the Impulse?

While Hero MotoCorp couldn’t be bothered answering that question for me, thankfully Amit Nangre, a diehard motorcycle aficionado from Pune, was thinking of the same question and he decided to take a stab at answering that himself. Ever the resourceful fellow, he bought himself an Impulse, ripped out the 149cc engine, sourced himself a 223cc mill from the Karizma and proceeded about the job of fitting it into the Impulse’s frame. Now while this might seem like open-heart surgery, and to a certain extent, it might be, you’d be surprised to know that it’s a far less complicated procedure than one might imagine, and nothing a bit of planning and ingenuity can’t see through.

The Karizma engine is based on the 230cc Honda engine which the Japanese company has doing duties on a large number of bikes internationally. Incidentally, the crankcase on this engine is almost identical to the one on the Honda NXR 150 Bros, the South American bike which Hero MotoCorp brought to India as the Impulse. So to fit the Karizma engine into the Impulse, all Amit had to do was slightly adjust some of the clamps on the top of the block and on the crankcase to be accommodated into the dirt bike’s frame, and voila – it was pretty much a direct bolt-on. The tip of the larger exhaust manifold from the Karizma engine was welded to one end of the Impulse’s exhaust system, a free flow muffler was added to the other end and the job was complete.

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Straight off the bat, as soon as you crank this hybrid machine, you know you’re riding something different. For one thing, it takes a little while to come up to temperature and maintain idle revs – a feature typical to the Karizma. Slot it into first, and the typical notchy Karizma gearshift also become apparent. But all you gotta do is open the taps and let the fun commence. Since the short final drive ratio of the Impulse has been maintained, you tend to lose out the top end the Karizma offers, but the acceleration from stand still is impressive, but what really took me by surprise was the mid-range pull. Any gear, any speed, open the throttle, and this Impulse leaps ahead with great gusto.

While this short gearing makes city commuting really fun, long distance touring is something that would need a revision of the gear ratios, even though the extra grunt does make the bike feel more relaxed approaching highway speeds. But if you really want to have fun, then you need to step into this bike’s natural territory – off the road. The extra cubic capacity means that you now have enough grunt to really fly on the roughest of terrain, and even up all but the steepest of hills. Be a little enthusiastic on the gas on loose surfaces, and you’ll have a blast sliding the rear.

There are however a couple of problems. The stock brakes on the Impulse really do not seem to have the necessary stopping power to handle all that extra going power. And the heavier engine does seem to have slightly upset that lovely neutral balance of the Impulse. But really, these are just nitpicks, and if the stock Impulse made us giggle like school girls, this one made us shriek with glee. So to try and answer the original question, why didn’t Hero MotoCorp plonk the Karizma engine into the Impulse? No clue really, but they bloody well should. It’s some of the most fun you can have on two wheels.