Have some doubts running across my mind for quite sometime now regarding 100-135CC 2-Stroke bikes which were available in India.
As a case study I would like to consider Yamaha RX-Z 5-Speed & Suzuki Shogun compared against a Pulsar 150 & Honda Unicorn 150. I understand that while considering the power of a bike the BHP/Ton ratio and CC/BHP ratio are quite important as per many bike magazines.
If we consider BHP/Ton ratio of RX-Z it comes around 121.7 BHP/Ton whereas that of a Unicorn comes around 95.6 BHP/Ton. Now as per some sources, the Top speed of an RX-Z is mentioned around 105Kmph (Stock) and that of a unicorn is 113Kmph (Stock).
Now, both these machines are close to 14BHP (Unicorn being 13.5 to be precise, which is 0.5 BHP lesser), but still the RX loses out in the top speed segment.
Likewise if we calculate for a Suzuki shogun the BHP/Ton ratio comes around 133.33 BHP/Ton but as per the road test I had read in Overdrive magazine long back & some advertisement in one of the magazines its given as 105Kmph.
What I want to know is, how on earth are these newer 4-stroke bikes with 13.5 to 14.5 BHP (150CC Bikes) easily do beyond 110Kmph with more kerb weight compared to our yester years 2-Stokers which weighs not more than 110Kgs.
In fact in overdrive magazines, in the end there used to be vehicle details given along with price list of various manufacturers & there as well I have seen the top speed of RX 135 5-Speed (14BHP) given as 99Kmph, whereas Pulsar 150 or Unicorns given are in excess of 110Kmph.
In the sources URL which I have mentioned, even the top speed of HH CBZ & TVS Fiero is more than that of RX-Z !!!!
Can anyone explain why this top speed issues in case of 2-Stroke Indian bikes ?
:: BIKE TRACK TEST: CBZ - FIERO - RXZ - PULSAR 180
Shootout HONDA UNICORN v NEW BAJAJ PULSAR 150 DTS-I
PS: I dont want any battle here as to which is better etc etc, but want the technical reason for 2-Strokes being slower as per the data what i have collected.