Welcome to XBHP, 1st. 2nd, post it in the intro section about yourself. 3rd, if your 1st question about whether to buy Duke or NS based on the FE, then I guess, Duke is not your cup-of tea.
Go with Honda Dazzler or something. It has greater fuel FE. Duke has lower FE. NS may be slightly better off but both these bikes are meant for enthusiasts.

Duke gives about 30-32 kmpl. If you really want a bike for FE then I'd say buy the 200NS and ride it like a Splendor or Discover or for that matter Platina 100..

Duke is a bike for people who follow biking like a religion and not just a way of commuting. It is for true biking enthusiasts and not for FE.

Even NS is for enthusiasts but Bajaj has made some tweaks in the engine to make it a tad-bit fuel efficient. Bajaj claims that if you ride it @ around 50kmph then it gives an average of about 58kmpl. But then what's the point of buying a 200cc bike.

No offence.. Just making a point

I just want to confirm It can deliver 35-40kmpl.

It can, but only if you never ride the bike the way it was designed to be ridden. As others noted, if all you're concerned about is fuel economy, buy one of the little bikes, and use the cash you save to dress it up so it looks more like a performance bike. You'd be wasting money buying the Duke if you're going to try to wring every drop of economy out of it.

Also, to be honest, both this and your original question really belong in the What Bike forum, not the ownership thread.

I'm also new, to buy a bike. Decided to buy Duke over NS. I too had confusions, but sorted out.

Reasons because of Technology:

carb + triple spark-plug + SOHC + ... SOHC + Tiny CatCon' V/S 'Single spark + Fi + DOHC + Bigger CatCon

First one is NS, second is duke. Only advantage is triple spark in NS over DUKE.

Besides these, Superior in braking, suspension, frame, color job, everything is good and class compared with NS.

forget the number of spark plugs .. even ducati , bmw , yamaha , aprilia etc dont use these many spark plugs in their bikes .. does it mean that bajaj is having the best tech ?
the point is that , the number of spark plugs depends on the design of the combustion chamber .. if the combustion chamber is designed to accomodate 1 spark plug , then 1 is enough ..there would be no extra advantage in trying to stuff more spark plugs ..
remember that duke is fi and the fueling will b precise , unlike carb in ns .. 3 spark plugs would be needed to avoid the disadvantages of carb ....

i had booked ns but bought duke .. i honestly feel that there is no point in buying ns if you are able to buy duke ..

I also preferred Duke over NS. Read cleanly bro.

Also stated 3 spark plugs is the only advantage NS has over Duke. (Definately more spark plugs -> to increase life time in combustion) Sources: Everywhere, just browse through.

Also mind, u helped me lot, i read every posts of questions regarding NS vs Duke and their replies.

I also booked NS, and cancelled s'day. Enhancing my purse to Duke Bro.

Nothing as offence Bro!

I'm explaining what i know.

To have multiple sparks (like quad or more), combustion chamber has to be large in size, its not feasible (to have multi), though it is possible.

Regarding its advantage follow these links..,

Patent US7992542 - Multiple spark plug per cylinder engine with individual plug control - Google Patents
Internal combustion engine with multiple spark plugs per cylinder and ion current sensing - Patent #07677230
Engine & fuel engineering - Multi Spark Plugs
Spark plug - Wikipedia, the free encyclopedia
Why?? two spark plugs per cylinder on my car??? - Yahoo! UK & Ireland Answers

Also i meant triple spark is the only advantage NS has technically over Duke.

And also don mistake, i'm not comparing NS and Duke. I'm comparing Single vs Multi Spark.

FI, DOHC, Small CatCon, Dual exhaust mufflers, Steel Trellis Frame, Close-ratio transmissions for quick acceleration,,, are technical highlights of DUKE - Im not neglecting this!

[QUOTE=Rohan200ns;847285]@AnupamOnWheels -- i meant that the bike jerks when the rpm goes below 2000rpm ..it is all normal when we pull the clutch .. we are not supposed to ride it below 2000rpm right.. in all the reviews they have told that the fueling is snatchy below 2000rpm .. i
think that is the characteristic of duke..
QUOTE]

I remember reading about the fuel injection doing that at lower RPM on a lot of brands..!

The whole point of multi-plug heads is to compensate for an inability to fully or evenly combust the fuel charge inside the cylinder. Either the flamefront is asymmetrical, resulting in uneven cylinder pressure, or the flamefront doesn't reach all "corners" of the combustion chamber before the powerstroke has progressed too far, resulting in some fuel remaining unburnt (wastage). On a motorcycle, this is almost unheard-of due to the very small volumes of the cylinders. Even on the "big" 600 and 650 singles, or the really big V-twins, multi-plug heads are almost never used, even in racing applications.

That Bajaj would use a triple(!) plug on a bike that displaces less than 250cc smacks of either marketing gimmicks or an extremely poorly-engineered engine. No bike that small needs more than one plug. If they're really having that much trouble with incomplete combustion, they need to look at reshaping the combustion chamber, possibly even something as simple as having the plug project further into the chamber to expose the electrode more (or better, get smarter engineers). If it's just a marketing gimmick, then it becomes needless complication. Either way, Bajaj is due nothing but ridicule for selling a bike like that (either their engineers are incompetent, or they think their customers are idiots).

NOTE: This is a gross OT post as this is a Duke 200 ownership thread but the sheer dismissive posturing of your post towards genuine and engineering logic dictated efforts of the R&D of our country's principal two-wheeler manufacturer perforce compels me to reply here. We can take this discussion further in a separate and new thread if you feel so.

The use of multiple plugs in engines has been around since the early years of aviation though the reason there was a need for a back-up substitute of a critical component in the interest of engine reliability rather than a gain in combustion efficiency. The gain though was there and in that case an incidental benefit.

The 'deficient' flame-front is just one of the many issues addressed through the use of multiple plugs. A small 200cc engine here is expected to produce good tractability at low rpm's allied with sufficient power at high rpm's with a low fuel consumption and also to meet with strict emission norms. Even basic awareness of reciprocating engine parameters puts it in the clear that the first two of the above are conflicting requirements unless supported by allied flow or combustion enhancing technologies that work in tandem with the basic engine. Things like variable intakes, variable cams, dynamically switchable maps etc. A 200cc engine fed through a carburetor has an appreciable specific power output in the range of 117 bhp/ltr without using a high compression ratio (a parameter that invariably creates more issues than it solves due to the ubiquitous adulteration in the fuel sold to us in this country) needs some special measures to harness as much combustion efficiency as can be done. Add exotic technology for the same and see the price shoot up. The Duke makes do with a single plug but runs an FI system with a high compression ratio and does not return the fuel efficiency figures that the 200NS engine does.

The 'bigger' engines do not really need multi-plugs. True. But for reasons that there's other stuff to substitute for this 'not so easy' way out. Will come to the difficulty a little later. The reasons first. 1) there's enough cc's around to produce enough low end torque with better flow even without special measures and the engine can be designed keeping high-end power output in mind 2) the really thermally efficient (high specific power output) engines have a slew of technological gadgetry that assists flow and combustion control. 3) these engine invariably rely on high compression ratios to flatten the torque curves and take the power higher 4) flexibility is not a prime requirement and so the engines' characteristics can be purpose-specific in design.

The 3-plug head is a casting engineer's worst nightmare. Maintaining dimensional tolerances in such a thermally intensive and mechanically punishing environment with a head perforated like 'Swiss cheese' is not what any engineer would want to design to unless the gains outstripped the problems by a large margin. If only I could share with you the flame propagation time comparison of the 3-plug head vs a single plug and the DTSi engine, the peak flame temperatures, the temperature gradient wrt to time and the peak cylinder pressure vs enthalpy curves would it be a lot easier to convey the elegance of the 3-plug head as an engineering solution. The NS200 engine btw meets with the stricter emission norms without the need for a catcon or any other ancillary support componentry.

@Anupam; @Mountain; @oldfox',
All the above discussions by you all are OT for this thread, but its like bike EDUCATION for us.
Loved reading those.

yes i agree .. we are not supposed to ride a short stroke motor at very low rpms..by jerking i mean that the throttle response is too sharp and it just sends a signal to me that it will stall if i dont downshift .. i have had to brake suddenly a few times , i used both brakes equally so it stopped gracefully .. i am sure that people new to rear disc brake will definitely lock it up during panic braking..
bro i enquired about the prices of ls2 helmets in a big showroom .. they give bill , warranty etc .. it is definitely not fake .. btw , ls2 make different sizes ??

+1000 to that ... moreover fi is so precise in fueling that there is no need for extra spark plugs ..there is no wastage of fuel ...

superb tech. explanation, i completely agree with it . its 100 percent true that a small engine like 200cc ns does not even require a twin spark plug if it is designed properly either the airflow design, head shape is poor or it is just a marketing gimmick. The twin spark plug tech was launched a long time ago in cars which with advancement in technology was put off . Now with Computer optimized designs we are able to eradicate need for it quite easily so. Also an observation those who might argue that slightly better FE of ns is because of triple spark plug, no it is product of smaller Tyre size and taller gears optimized for FE compared to short gearing and the biggest tyre sizes of Duke including Ninja, this side of 650cc. . Also being patriotic does not mean we will agree with whatever comes by even if it is incorrect or not needed towards advancement in technology