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 )

@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.

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.

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.

Everyone has already mentioned that shorter gearing is the reason why Indian 2 strokes do not have a top speed as high as the 4 strokes. 2 stroke torque curves are not as flat as the 4 strokes. 99% of the total riding done on 2 strokes is done at lower engine speeds where the torque produced by the engine is less..less enough such that the engineers feel the need to make the gearing shorter in order to improve rideability of the bike. Such problems do not exist on 4 strokes because of the much cleaner gas flow and combustion over the entire engine speed range results in much better torque production.

Seriously Renny u wud be helping me a lot.What kinda sprocketing can bring up that amount of Top end on the Shogun ?????.......suggest me pls.I need to put those mods on my bike.
I am now going for a 13/40 Top end increase instead of stock 13/44 which is heavily biased towards acceleration.

Also I knew that 2 strokes produced huge amount of low end torque and they did not require shorter gearing.If I consider Yamaha and Suzuki 2 stroke bikes separately,Yamaha always had taller final drive ratio than Suzuki bikes, which means they need not worry about torque.

But...but ...but, I am comparing here two bikes
take for example,
Suzuki Shogun 14bhp/11.4 Nm torque
Yamaha FZ16 14bhp/14Nm torque
which means a 2T is heavily biased towards Bhp generation,Very good High end.But sorry on low end.Which means if I carry out a sprocket job on My Shogun,it will behave like the R15...........small low end but huge top end.Which means I have to rev the bike hard always in city traffic.While the actual thing comes up on highways.Which is all but very good thing

However Yamaha 2ts are different, RX135 produced 12bhp power with 12.25NM torque,looks like an FZ16.So anything cant be concluded here.Hence its different treatment for different bikes.

there is a very interesting comparo between a FZ 16 and a RX100 in this month's autocar or overdrive. It will surely answer a few more questions because even there the RX100 has a higher power to weight ratio than the FZ. Check it out.

That was a neat explaination given. Let me just put in some good practical gear ratio figures of some of the common bikes & let see if we can get more inputs from all the experts here.


I think if you can see there is not much of a difference between an RX135 4-Speed & Fiero ratios, but still there is some appriciable difference between the top speeds of both these machines (I am comparing stock to stock here).

Same thing goes true for RX 135 5-Speed vs. P150 vs. FZ-16.

I fully agree that the speed-torque (N-T) curve is quite different for 2-Stroke vs. 4-Stroke, but my question remains, Is BHP/Ton & CC/BHP not important at all for an IC Engine ?

An RX 135 is such a light machine with 14BHP, but still is not able to match the top speed of a P150 or a Unicorn (in stock condition).

And one more thing here, the sites i had mentioned in the opening thread are really reputed ones & the straight line speed was tested using GPS and not the bike Speedo unit. Also car-bike magazines like overdrive & auto-india are really reputed again & why would they simply mention top speed of RX 135 as 99Kmph ? Trust me, they had given the top speed of Gladiator as 108Kmph & this had really made me thinking.

And if we have to go by what company says, then while launching R15, company showroom had banners displaying a 145Kmph top speed, but we all know the true top speed is only 130Kmph which was measured by these reputed car-bike agencies.

All you guys can pick up an old edition of overdrive (2002-2004) & check it out for yourself.

All i am saying is, it feels sad to be smoked by a newer 4-stroker & only option left is to modify the existing 2-stroke, which always is not a good option.

- Karthik..

Gearing is not the only factor, the absolute engine rpm also matters. where a RX135 will not rev to above 8000 rpm, a fiero will go to 9000-10,000 rpm.