The Ambition is a scaled down CBZ but with a raft of detail changes which have made the bike more peppy despite giving up on displacement. First off the Honda boffins have gone low down on the cylinder bore of the CBZ engine while keeping the same 49.5mm stroke. The 63.5mm dia piston has given way to a 58.5mm dia piston which makes for a 133cc engine capacity. The CBZ mill did come with very many gadgets like air induction, TPFC and the like but the fact is that it is very rough in the upper reaches of her Performance band and therefore top end Performance is not a strong point of this machine.
The need to offer a similar powerplant but with a smoother power delivery while also remaining crisp and buzzy meant that the ignition system had to be given the once over as also the carburation. First off, even though the engine displacement has been reduced, the Ambition benefits from a larger air box which always helps engine breathing and it shows in the crisp engine response whenever you crack open the throttle.
But the biggest gains have come by way of the AMI or Advanced Microprocessor Digital System which is in effect a digital CDI system of the type pioneered by TVS for its Fiero. A set of dual programmed ignition curves is at the heart of this ignition system.
A Keihin PDN1A carburettor is employed and this side draft unit with variable venturi (21mm dia) also features a throttle sensor which depending on the throttle opening provides inputs to the AMI ignition system to activate the right amount of ignition advance or retard depending on the power requirement.
Both these ingredients have helped smoothen off the rough pulses one experienced on the CBZ. Ride both bikes and the smaller 133cc Ambition impresses in its power delivery and revvy nature while also laying the power down On the Road in a pleasing manner. These also help to deliver very good Fuel Efficiency for a bike of its class.
The Ambition sports a specially designed dual colour muffler with an air injection valve built into the system (just near the exhaust port). This helps cut down on carbon monoxide emissions while the air cut-off valve helps prevent burning in the muffler. And like so many bikes in the country, the exhaust note is mellow, just not striking the right audio notes to enthuse a hard-core biker. When will our bike makers learn that a great exhaust note can also be a great marketing tool?
In the suspension and handling departments, I think that Hero Honda has got it right for the Splendor-Passion types whom they want to take to a higher plane. Anyway the suspension and the frame can't do much to delight in the form they are in at present and to compound it all, the riding position is all wrong for the sporty types but oh so Passion-ately correct. Now does that ring a bell, anyone?

Adil Jal Darukhanawala