Query Approved

The KTM Duke 200 and Pulsar 200NS engines are 2 of the least mechanically stressed engines available on Indian bikes in the country. There is already an ECU remap available for the Duke which increases the Rev-limiter to 12.5k RPM, boosting the power output to around 28 bhp. Even at this increased rev-limiter, the engine is less mechanically stressed than that of a Pulsar 220 at redline. Joel kits might get available in due course for the Duke but even as of now, it has enough upgrade potential with just a simple ECU remap.

IIRC its 11.7k rpm

Source -> 2012 KTM Duke 200 gets a remap option by Indian tuning firm Kiirus Autosport, that pushes up the rev limiter to 11,700 rpm, in an ICB exclusive | IndianCarsBikes.in

Sorry bro, but although the 125 was launched ahead of the 200, design-wise it's just the other way around: the 125 is a reduced version of the 200 for the European market (and some others?) which allows people with only a car driving license, or from 16 to 18 when they cannot yet drive cars, to ride 125cc. bikes maximum. The young ones over there are mad about it....but mind the cost: >5,000 Euros!!!
There will soon be a 350.

There is also a Yamaha "FZ-12.5" that is a reduced capacity FZ-16 sold on the Russian market. Has not made it's way in Europe, as far as I know... (?)

The Duke 200 is effectively already known as a sturdy bike (and the 125 would be indestructible!), and even shares some components with the Duke 690: KTM really wants to live to its reputation! I have a FZ-16 but I wish the ridiculous law we have here (in Vietnam) limiting the capacity to 170cc unless one has a "special" license (VERY expensive= mean stick the money in my pocket!) was allowing 200 or even 250cc (an Internationally significant capacity) : the Duke is soooo much better than a FZ-16....but maybe then I would have gone for the 250 CBR???

The official akrapovic exhaust is out of the duke but i hear it doesn't give any real performance gain.
Any mod other than an good exhaust will reduce the reliability of the engine be it ECU remap, airfilter change, bore-piston kit, etc
The duke is already a high compression engine. If you have observed the engine temperatures you will know that its not a cool engine. a bigger bore will further increase the temperatures unless you do some work on the head as well...
If you are going for mods be prepared to accept the increased maintenance and lower reliability than stock.

WOW!

KTM200 and P200NS are not "one of the least stressed engines"

this does not mean, there is no or very less potential for further mods, coz almost all production engines have a lot of modification potential.

stress level comparison with P220, well, there's another thing called, good design, bad design and an average design.

+1 ,

Duke 200 is Duke 125 with an increased combusion chamber. I hope there should be a very less potential left. Also upon seeiing hte factory rev-limiter I feel the reliablity will be a question at high revvs with this compression ratio. Airfilter, iridium spark etc should not have a noticable impact on the power delivery.

You can try Sprocket combinations as per your need. All applies to Pulsar 200NS as well, coz basically when you fill a little more air on P200NS it becomes a Duke200.

Could you please elaborate it. Not able to get the point here..

Could you please elaborate the reasoning behind the quoted text? I am not as technically adept as you are so asking.

Because I was of the opinion that mechanical stress on an engine can be satisfactorily calculated by using a parameter called 'Mean Piston Speed'. Higher the mean piston speed, higher is the friction between the walls of the cylinder and the piston, and higher is the stress on the oil to perform at its optimum and in case that doesn't happen, higher is the chance of engine failure.

BUT, for a fact, due to the short stroke nature of the 200cc engine, the mean piston speed of a Duke / 200NS engine at 'rev-limiter' is lower than any 16+ bhp bike at 'redline' sold in the country (As far as I have checked purely mathematically).

Going by the very same reasoning, the P220 engine is the most stressed engine sold in the country for all bikes < 35 bhp.

The mean piston speeds of the following bikes at 'redline' are mentioned below:
Duke / 200NS : 16.33 m/s
Pulsar 180 : 16.92 m/s
RTR 180 : 17.34 m/s
Ninja 250R : 17.85 m/s
RE 350/500 : 18 m/s
CBR 150R : 18.09 m/s
Karizma R/ZMR : 18.76 m/s
CBR 250R : 19.25 m/s
R15 / V2 : 19.57 m/s
Pulsar 220 : 20.8 m/s

Just for reference:
Triumph Speed Triple : 21.42 m/s
Ducati 1199 Panigale : 22.29 m/s
BMW S1000R : 22.37 m/s
Renault RS27 F1 car : 25.8 m/s

From what I understand after reading this link is that to withstand the extra mechanical stress due to higher mean piston speed, anything above 20 m/s requires "forged crank, peened rods with good bolts, forged piston" and anything above 25m/s goes into drag spec (forged crank, Aluminum rods, lighweight pistons, etc.).

As far as stress on the engine due to a higher compression ratio is concerned, that can always be managed by using a beefier head.

Of course, all my knowledge in this regard is secondhand and not firsthand like you so please feel free to correct me if I am going wrong anywhere.

@ antz: technically you asked the question to harish about what he posted. i am not going to comment on what he wrote, but just my 2 cents-->

• you are very good at numbers.
• according to your numbers, RE, karizma, R15, CBR are all very near to that 20m/s limit, after which the engine needs extra mechanical measures to safeguard itself. and these bikes mentioned above are way above Duke/P200NS. so according to this theory, these bikes should have very high engine failure rates. but i don't think that is the case, we all know how reliable these bike are. think about karizma and what are its engine failure rates or duration between engine rebuilds, or how much it goes on stock bore and piston. infact pulsar 180, whose mean piston speed is much lower than karizma is considered much less reliable or conceived as having much more engine trouble. my point is mean piston speed is just one of the several factors to know how stressed an engine is.

-----

Just going through the wiki article, I honestly have no clue on what mean speed has to do with Mechanical stress. "It is a good indicator of the class and performance of an engine relative to its competitors." is what is mentioned. How do you relate Mechanical stress with this?

My understanding was though you operate the engine at a constant 7000RPM the engine will be stressed differently with respect to what gear the bike is operated. Mechanical stress depends on the power extraction done at the gear box, be it any RPM. As per your thought Duke 200 has one of the least stressed engine at 10500RPM, then why an engine cut-off placed right there?

Anyways what I was about to convey is,

1) Duke 200 is one of the most extremely short stroked and short geared bikes in India. Shows how hardworking the engine is, an aftermarket re-bore to this stroke length could be done only if you have excess faith in God.

2) With this extreme hardwork the engine is capable of producing 25BHP at 10000RPM and without any second thoughts the engine operation is restricted to 10500 Runs Per Minute from factory, which means KTM has put a limit to the optimum stress to which the engine/piston can be operated safely is 10500 Runs Per Minute. In the case of R15, the Daytona ECU voids the warranty. Removing the cutoff is at your own risk and you may end-up blowing the engine.

Remember CUT-OFF is different from RED-LINE.

PS: No offense to anyone/thing here, Duke engine is quite hard-working it doesn't mean its less reliable, coz the quality of components used would bread the engine to do such a hard-work.

@Harish, the 2nd link in my earlier post explains in detail the significance of mean piston speed. If you are having trouble opening the link (like I am) try viewing the google cached version here.

Well, to let you in on a secret, I am not that good with numbers. I use Google Docs . Its fast, its simple and its free, do try it once .

The keyword in my previous post was 'at redline'. Bikes like ZMA and REs have nothing to offer when riding 'at redline'. Both these engines being long stroke units which make peak torque and power much much below where the redline is marked at on the tacho. There is no use of slogging those engines as the sweet spot is much below the redline. Naturally, those engines will be run much below the redline for a more fruitful ride. Just ask a hardcore bulleteer what will happen if he keeps riding his bullet at 6k RPM continuously.

By comparison, Pulsar 180, RTR 160/180 are high revving short stroke engines with poke all the way till redline / revlimiter (and beyond in some cases). These will definitely be revved higher than an average RE or Karizma and will definitely be run close to redline much more often. Doing this *after* your oil goes bad is what spells the death knell to these engines. By keeping the peak MPS comparatively low, what BAL / TVS have done is that they are playing it safe and keeping costs down at the same time!!

Just so you know, the 1st gen RTR 160s came without rev-limiters and could easily be revved to 12k+ RPM without causing engine failure/blowups even though the redline was marked at 9k.
Reason: RTR160 (15.87 m/s) happens to have an MPS even lower than the Duke.

Coming to the R15, Yamaha know that this bike has the power-band conducive for redline to redline revving. And thats the reason the YZF-R15 is equipped with an all-aluminum cylinder called the DiASil Cylinder and a forged piston!! *Surprise Surprise* . Of course removing the revlimiter and using the Daytona kit will void manufacturer warranty. But it won't look nice on the part of Daytona AND Yamaha if engines kept blowing up even after using expensive official performance kits.

I am sure that both CBRs, being premium products themselves, must be employing similar technology to work around this issue (Could someone please pull that up for me). Thankfully, Yamaha mentioned it right on their official website for me to quote from .

Coming back to topic, We have to agree that Some engines are inherently more capable of running at sustained high revs than others due to their basic design (bore / stroke). You cannot run an RE at 7k RPM because it will kill the engine instantly (MPS rises to 21m/s) whereas a Pulsar 180/220 engine will relish the opportunity and keep on going at the very same 7k RPM all day!

Similarly, super short stroke engines like Duke 200 / CBR150R / Ninja 250R, by design, are comfortable at revs that will easily kill a Pulsar 180/220 engine. Conventional wisdom might not allow us to accept this fact very fast, but the Duke engine (not unlike the 150R/Ninja engine) is anything but conventional when it comes to the Indian marketplace. Why they do not use its potential fully I do not know, but just in case if you do wish to over rev the Duke, it comes with lightweight forged piston and crankshaft alongwith forged con rods as stock which will ensure that you are not left with a blown engine if you do venture above the extremely mild 10.5k revlimiter.

do you agree that there are a lot of other factors that count while deciding whether an engine is stressed or not....apart from mean piston speed???

Of course, I definitely agree, thats what I wrote in my initial post

The stress taking capacity of components used is equally important.

But comparing a case where both sides use forged crank and pistons. One has a MPS of 16.xx and the other has an MPS of 19.xx which, do you say, is more stressed ?

i will say "probably" the engine with 19.xx MPS,

but the next question that comes to my mind is if the engine with MPS of 16.xx is indeed less stressed, then why is it restricted to an RPM limit, it can touch even in top gear.

if i am an engine designer, and i know i have designed an engine that is say- less stressed, i will allow it to rev it more to extract as much performance as possible. isn't it.

also, i would like to know from other members as well, does the ratio of BHP to CC is any indicator of how much stressed an engine is.