Thread: 2-Stroke Indian Bikes.....

Dear xbhpians,

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 ?

With Regards,
Karthik..


Sources:

:: 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.

Ouf! That was a long one.

Approved

For the last part about 4 strokers having a higher top speed, well it depends greatly on the engine design and gearing as well. The 2 strokes might have higher acceleration in comparison, but owning to shorter gearing to maximize the power out put, they run out of steam at the top end.

and iirc the top speed of a RXZ 5 speed is claimed to be 110 kmph as per the company.


Also for the query before that one. Ill be getting a RX-K block soon. So ill update you on the quality and finish.

Also is there any difference between a RX-K con rod and indian RX con-rod?? i dont think so, since they are the same bikes?? ( other than the RX-K con rod being imported )

Originally Posted by karthikdattag

I fully agree with him but still feel that 130Kmph should have been reached. I have street raced with RX100, RX 135, RXZ, P200 & ZMA on Mysore-B'lore highway & NICE roads & never lost to them in acceleration or top end, but somehow i feel more could have been extracted out of this motor

@karthik: We at xBhp do not promote street racing in any way, on road, as well as online. i would request you to take proper care and discipline on public roads. Thanks

its too long to discuss about each topics but about four stoke and 2 stroke .2 strokes are faster than 4 stokes and the top speed depend on conditions.

its all about engine gearing and load..both engines have diff characteristics

TWO strokes are about madness, the rush, the smoke, the noice, the kick, the adrelin rush.

If you want top speed, do sproaketting man to achieve 130-140kmph on shogun.

Originally Posted by jd666

Also for the query before that one. Ill be getting a RX-K block soon. So ill update you on the quality and finish.

Also is there any difference between a RX-K con rod and indian RX con-rod?? i dont think so, since they are the same bikes?? ( other than the RX-K con rod being imported )

Hey buddy, any updates on these RX-K blocks? I have seen these in person in Yamaha showroom, but have not seen any bike running with it or some performance figures. The port sizes looked similar to a 4TL-10 kit.

Any new update would be appreciated.

Originally Posted by jd666

and iirc the top speed of a RXZ 5 speed is claimed to be 110 kmph as per the company.

Correct ... the owner's manual says "use gear 5 for speeds ranging from 50 to 110kmph and above

@kartik - my block is on the way. once i get my hands on it, i will surely update everyone.