In my 22 year racing career, I have ridden a variety of racing two-stroke motorcycles ranging from Villers engined Enfield bikes to thoroughbred racing motorcycles from Honda and Yamaha. The first thoroughbred GP racing bike I owned and raced was a piston ported liquid-cooled Yamaha TZ350 G. In the early 80s, Yamaha TZ motorcycles were the forerunners in motorcycle GP world championship.

Aspi Bhathena on a Honda RS 125 rides right around Irfan Sharif (also on a Honda RS 125) at the Chennai racetrack

The piston ported TZ350 was one of the most difficult bikes to ride. There was no power upto 7500rpm after which there was a gradual gush upto 9500rpm. Beyond that, the actual power band started churning out a whooping 65bhp. The bike felt like an untamed beast to ride compared to modern day machines as the chassis which was constructed from steel tubes tended to flex and crack under stress and vibration. The manic power delivery above 9500rpm further made it difficult to control the bike especially around corners. All in all, it was very challenging to tame this motorcycle and getting the best out of it was even a bigger challenge. It was my first thoroughbred racer and I still have fond memories of riding it.

The second thoroughbred was the Honda RS125. It is one of the sweetest motorcycles I have ever ridden. With a single cylinder liquid-cooled crankcase reed induction system, the little Honda pushed out 45bhp and weighed only 72kg giving it an excellent power-to-weight ratio. The crankcase reed induction made sure that the bike had a wide spread of power. From 7000rpm the useable power would keep building all the way upto 10,000rpm, beyond which the bike became a screamer right upto its 13,500rpm redline. The bike’s smooth power delivery and an excellent aluminum beam chassis also made it a real pleasure to ride. All you needed to do was just point the motorcycle in the desired direction and lean your weight towards the inside of a corner and it would go around the bend like it was on rails. The little 125 is still a great bike to ride even today as it doesn’t frighten you to death with its power delivery.

The Yamaha TZ250 V-twin was the last motorcycle I raced. The V-twin motor was liquid-cooled and had a crankcase reed valve induction. It was also equipped with exhaust power valves to make it more user friendly. This particular motorcycle was raced at the famous Daytona Speedway in USA and finished second. The experience of riding this bike was something else as it developed in excess of 80bhp and weighed in at 90kg giving it a smashing power-to-weight ratio. The power delivery of a racing motorcycle is very different as compared to road going bikes. The acceleration is far more vicious compared to street bikes which develop the same amount of power or even more.
 

Aspi’s highly modified RD350 based race bike. The bike ran a TZ350 gearbox and a custom built monoshock system

The V-twin Yamaha TZ250 was one of the most popular two-stroke bike amongst national and international bike racers

Riding the TZ250 with its alloy beam frame gave you a secure feeling as there was hardly any flex. You really had to use all your body weight to get the bike to turn in corners. The acceleration of the V-twin motor was something that you treated with respect. As you got going in the first gear it was diffi cult to keep the front wheel down as the engine hit the power band. The power valve on the TZ made it a little more rider friendly as useful power started from 5000rpm to 8000rpm but from 8000rpm to 12,500rpm is where the real power band lay. This 4500rpm power band was like a luxury as far as racing two-strokes go.

Riding two-stroke racing motorcycles for fun and racing them are two totally different ball games. The speed of these bikes is such that it makes you feel numb. The last time I raced the TZ was in 1999 and I put in the best lap time. Riding these motorcycles can drain you out totally and you could lose up to a couple of kilogram in a day.