Sprockets? and
Not really mate, I had a P180 ug3 which used to hit its revlimiter too in top gear (stock).. 128kmph @10.x rpm
just crouching was sufficient to hit the revlimiter and it used to get there pretty fast too..
This engine swapping excercise is getting pretty confusing now

Sir, I said the same. I mentioned that the 223cc R15 will attain more than 126 kmph (ZMA top speed) due to that light weight aerodynamic fairing. Also, the overall chasis and body setup would help it attain >126 kmph speeds.

On the other hand, the 150cc ZMA will not reach the earlier top speed of 137 odd clicks (R15 approx top speed) because:
1. Kerb weight increased by 20 kgs
2. This engine will have to make do with 5 gears instead of 6.

Waiting for this one!

@Satyen: What's so funny?
No we said different things.
I compared speeds of the same bike (stock vs modified bike)
You compared speeds of different bikes (donor vs recipient bike)
Since both engines make the same power, try to treat the engine as a replaceable module.
Exactly!! If we now undergear the 150cc Karizma by 17.64% since it is now shorter geared, some of the acceleration deficit will reduce bringing it closer to stock.

Consequently, If we overgear the 223cc R15 by 15%, some of the crazy acceleration will be lost making it closer to stock.
But:
1. Both modified bikes will reach the same top speed as their stock equivalents.
2. Both modified bikes will redline in all gears at the exact same speeds (not RPM) as stock.

Now disconnect the Tachometers. How will you now tell what's happened (without peeking i.e. )?

Well I guess mileage figures shall say that there's something wrong with the ZMA 150 and R223 (223cc R15 )

Antz.bin - so what I said is also correct ?


ZMR generate peak power of 17.6bhp at 7000 rpm whereas the peak torque is 18.35 Nm at 6000 rpm.
RTR generates maximum power of 17.3 Bhp at 8500 rpm, with a peak torque of 15.5 Nm at 6500 rpm.

The time of Peak Power & Torque different will be there in both bike ?
So this statement will also be true then ^??

So its not about how much torque a engine generate but the way & ease it does is also an important factor ?

@ Antz.bin: you are trying to explain something by giving a more complicated example.

Have you taken over the duties from Baaba Sawaali?

Original Question:
I have always wondered whenever I see the specs of a hero karizma, what is the difference between this bike which generates 17 odd bhp of power and the RTR180 which also generates similar power, even though the former has a good 40cc bigger engine? What will the difference in performance be? Where is the catch? Same for other bike pairs like duke200 and the cbr250r, r15 and RTR180 and so on!

Possible Answer 1:
Every engine manufacturer has a specific need from the engine. Power/BHP are two of the many variables a manufacturer guns for. The bikes you compare are very apt examples to discuss further.
The RTR deploys a shorter stroke to ensure the bike caters to "Sporty" feel, quick rev build up and fast build of power is required. The Karizma however deploys a long stroke motor. This engine is not build for fast acceleration, but instead is build for better low end torque.

So does that mean the Karizma engine is more reliable than the "stressed for bhp in lesser capacity" RTR?
NO! Reliability is a function of many things like say the grade of components used, the "efficiency" of the engine design, etc. The engineers building the engines are not duds like us. They know what "stress" the engine would be going through, and so will equip the bike with the components that can last and take that stress.
So does that mean Karizmas engine is made of lesser quality component?
NO! Read the same explanation as earlier

I was only trying to build on the discussion by leading to an answer more substantial than "Both are as reliable as they need to be" which, IMO, is not really a *catch*. If however the Thread Starter and the readers are not interested in digging deeper for an actual *catch*, I would be more than happy to stop wasting my time on this thread. My interpretation of the query was "If it is easily possible to give high power from high cc, why go through the trouble of making more power from less cc? What ulterior motive do the manufacturers have in doing such a seemingly stupid/smart/over-smart thing?". I am sorry if this interpretation was wrong.

Re: Same power, different cubic capacity - what's the catch?

You articulated one of the chief points I would have loved to build on here. That's why I rEad through the answers. Thankyou for the exercise. Complicated though it may seem, it brought in a lot of understanding. Exactly what I wanted. My next question, or rather topic for discussion would've been that. Why settle for that power reading when more Is possible?

Sent from my WT19i

Maybe the guys at erstwhile Hero Honda were too conservative. They did not build a new engine. ZMA takes its engine from Honda CRF 230 which is a 6 speed type. Also, they detuned it from its original spec (18 HP @ the rear wheel) to 17 HP (@ the crank) for the ZMA. Same for ZMR. They added 0.6HP and increased the weight by 10 kilos.
Hence a ZMA is faster than a ZMR. (very minuscule difference b/w the 2)

Yes, it may be capable of making more power, but as Satyen said - all bikes cater to a segment and are made for a purpose.
It was BAL which showed that there's no harm in breaking barriers.

Let me bring the Yamaha Vmax and R1 into this-
Vmax-1670cc, 200 BHP@ 9000 RPM, 168nm@6500 RPM
YZF R1- 998 cc, 180BHP@12500 RPM, 115nm@10000 RPM

Still the R1 is quicker, faster. Is it due to the fact that the R1 has a significant over rev? Where does the extra power in Vmax go then, I can understand the torque.?

bro, you are not wasting your time, when i was reading through the posts, i sort of lost track of who is trying to convey what, and felt that example was a bit too much complicated.your interpretation of question is correct but just that answer could also be simple.

Re: Same power, different cubic capacity - what's the catch?

This is where PWR kicks in. Many people dismiss it as a vestigial parameter. Not so. That's why PWR is important. The R1 has mind blowing PWR compared to the VMAX. Pegging the two bikes against each other is like pegging a bike against a modestly weighted car.

Sent from my WT19i

I guess, taking the scenario in India, the first tech laden machine - the r15 was from a manufacture who has been making tech laden bigger performance competitive machines, say the r1. The Indian counterparts apache and pulsar bought 180/ 200+ to counter that(more cc less tech, both having advantages & disadvantages over the r15, the bike as a whole and engine wise too). One thing that gave an upper hand to them is the price point at which they were selling. The r1 has to make and stay competitive in its segment making max power from a restricted(<1000cc) engine. So it has to be a high tech premium machine. They(Yam & Honda) bought the tech from their premium 600's and 1000's to their lesser capacity, 'Indian premium' motorcycles the r15 and cbr 150/250. Where as Pulsar(collaborating with ktm) started bringing modern tech right into this segment to attain growth in a step by step process(200, 390, ___, etc). Both make Big sense for that particular manufactures.


@the topic,
Bigger cc better power spread = Tourer's delight
Lesser cc better peak power = Sports

RTR 180 and R15 might make 17 bhp @ 8500 rpm's but at 4000 rpm, RTR 180 makes more torque. That's where the extra 30cc's go, ok? In simple words, you can't use the R15's 17 bhp if you don't take it to 8500 rpm.
Similarly, out of R15 and Karizma... Karizma is almost the king of low end torque in the Indian "under 230cc" segment. Leave its clutch in 1st gear and watch it lift its full weight with ease...
R15 lacks such torque at low rpms like 2000, 3000, etc.

In simple words, see the text below:

R15: 17~ bhp (with very less low end torque.)
RTR 180: 17~ bhp (with better low end torque.)
Karizma: 17~ bhp (with the best low end torque among the 3 bikes discussed here.) Getting my point now?

The low rpm power/ torque is where the extra 73 cc's of Karizma went... ok?


New Bikers who are not new to Torque/ Power concept, can do great by understanding one simple thing: Two similarly tuned bikes' cc's can be same, but their power can be hugely different. And the bike with more power is not always better, as it may have lesser low end torque... or perhaps more R&D done on it... or some other kind of tuning.

ZX 6R makes 123 bhp. Ninja 650 makes just 72.... But at 2000 rpm, Ninja 650R will pull better than ZX 6R, as the power graphs show. All due to tuning.