Following the dismal sales of the Rajdoot 350, Yamaha needed to make a comeback product, and the recent success of Suzuki's AX 100 demonstrated the potential of small-capacity motorbikes in India. In November 1985, Yamaha released the RX 100 to widespread acclaim. The appeal came largely from the surprise that its engine could deliver as much power as it did. Race conductors and authorities often double checked the engine by opening the engine block to make sure it was actually 100 cc.With its lightweight body and high power output, the power to weight ratio of the bike made it the best 100 cc bike ever built for mass production, as a result there is still a high demand for it even if almost 30 years has passed since its production. The RX 100 was quickly adopted by racers who recognized its potential in drag racing. Various modifications such as expansion chambers, porting, engine tuning, sprocketing and changing wheel sizes became fairly common. Furthermore, upgrades such as bigger carburetors, air filters, quicker throttle, disc brakes, an additional 5th gear, race pistons, racing CDI systems, upgraded tires and suspension dampening were released, allowing riders to customize their bikes. Tuned RX 100's have completed the so-called standing start quarter-mile in about 14 secondsa respectable figure, considering the much larger BMW-S1000RR 4-Cylinder bike can cover in 10.2 seconds. The bikes was manufactured between 1985 and 1987 and were knock-down kits,, from Japan and were assembled in India. Only the model produced in Japan had disc brakes. The bikes were sold in Peacock Blue, Cherry Red and Metallic Black stock colors. The only major changes that the bike underwent was upgrading from a 6-volt electrical system to a 12-volt system with the addition of a CDI system for improved ignition and timing. The bike's production lasted from November 1985 – March 1996. Stricter emission laws and regulations in India made the continuing production of the RX 100 impossible. The CKD model was then followed by the, RXG, with a taller primary and secondary reduction. It had the same lightened flywheel from the RX 100 that causes a jerky ride. It was replaced by the manufacturer by a heavier flywheel the following year. Then came the RX-Z in 1997, with a new chassis and a shorter wheelbase with the same primary reduction ratio as the RX100 but with a taller final reduction. The RX-Z was launched with sportier bodywork and produced at 6,500rpm. Following the RX-Z, the RX135 was launched in 1998 with the same engine as the RXZ but using the same chassis as the RX 100 or RXG. The RX135 saw a moderate success due to its refined power output and better fuel economy. Finally, in 2000 Yamaha launched the, 7,500rpm RX135 5 speed with a catalytic converter silencer. It failed in the market due to its poor fuel economy and was discontinued after two years. The RX 135 was later recognized as the quickest RX and has a cult status due to its rarity. A 5-speed variant of the RX-Z with front disc brakes also had a limited release in 2001 at a premium price tag. The final variant was a 4-speed RX 135 with a catalytic converter silencer, sporting a fuel gauge and speedometer with white dials which was sold very briefly from 2003 to 2005.
Successors
The Yamaha RX 100 production run lasted from November 1985 to March 1996. The model was followed by the 132 cc RX G,. This model was the reply to the stricter emissions controls, which later became the norm. RX G had an economy-minded engine configuration with the ports tuned to increase fuel-efficiency and decrease exhaust gas. However, in the market. The Japanese manufacturers responded in late 1997 with the Yamaha RX-135 and the RX-Z which had a tachometer and a sportier headlamp and body. Both were mechanically the same and the RX-135 received a lukewarm response. The market also saw five-speed versions of the RX-135s and RX-Z. The final variant was a four-speed RX 135 with a small type catalytic converter, sporting a fuel gauge and a speedometer with white dials which was sold very briefly in 2003–2005.
