As long as your rev increases the bike can accelerate I guess(not sure).Earlier generation of pulsar 150 can hit top-speed of 118 with just 12.xxbhp,main reason for that is the absence of rev-limiter(but it took its own time to reach this speed).One may even ask why the re-limiter is not close to the max power.The answer is simple,when you shift up the rpm drops every time so when you accelerate again you can pass the max power band every time in every gear.

Max power at rated rpm is at full throttle position therefore, when throttle of my bike is fully open and at 8500 rpm then only it will generate max. output 17 bhp, & when throttle is half open or partially open whatever may be rpm it will not be max output. So increasing rev. always accelerate the bike as long it is less than full throttle position as max power is at full throttle at rated rpm.

Now at FULL THROTTLE generally power curve is inverted U shape with different slanting & shape depended on bike character Increasing rev will not increase power out put indefinitely as soon as after peak power it will start decreasing. suppose if this is possible by increasing rev. we can generate more power indefinitely then we can generate huge amount of power with small capacity engine of 150 bhp with 150CC)

Rev limiter is set so that bike engine does not get damaged due to increased vibration, heat & load and is depended upon material properties.

Either it is close to max power output rpm or not fully depends on bike character(i.e. tourer, sports, street etc.)

Now when we up shift the gear, load is increased on engine therefore rpm decreases(Why? because changing gear torque is traded off with speed i.e. same power is used to run wheel at higher rpm by changing gear ratio all condition remain same) so what i used to do is, gear changing is supplemented by sudden increase in throttle simultaneously resulting in not much decrease in rpm. you have learn the throttle response of your bike to do this thing i.e. not decreasing rpm on changing gear

I am new rider just 20K km in front of wheel so my my ways, correct me if i am wrong.

Enough of this technical shit now let's ride the bike to feel the max. output/acceleration on our body not only on paper. just fly... your flying Duck but responsibility

Have a question in my mind, how come a exhaust kit can increase the power of a machine, I heard lots of time about it.

does anybody have any idea

Power of the engine is directly proportional to efficiency of fresh fuel burn per cycle (in four stroke it is four stroke /cycle & in two stroke 2 stroke /cycle.)

Fresh fuel along with fresh air from intake i.e air filter will get more space if there is good scavenging of last burnt fuel from last cycle, as if burnt fuel is still is in cylinder it will mix with fresh fuel+air mixture entering cylinder hence reduce efficiency & power.

And good exhaust kit can help take out(scavenge) the most amount of burnt gases efficiently by there design good gas flow design, pressure differential, back pressure etc. therefore increasing power by giving more space for freshly entered air-fuel mixture efficient burning.

Power Vs. Torque with RPM - Knowledge!

Fellow XBHPians,

Regarding engines, terms that measure performance mainly seems to be,
1.Power
2.Torque

But, these figures are often accompanied by another term, RPM
So, this gives a combination possibilities of 8, when engines are compared.

POWER

1.high power @ low rpm 16.7kW@8500rpm Vs. 13.11kw@10500rpm>
2.low power @ high rpm 13.11kw@10500rpm>

the vice-versa of these, i.e, a comparison with power values interchanged in above, I dont know if they exist in production.

3.low power @ low rpm 13.11kw@8500rpm Vs. 16.7kW@10500rpm>
4.high power @ high rpm 16.7kW@10500rpm>

TORQUE

5.high torque @ low rpm 15Nm@7500rpm Vs. 12Nm@8500rpm>
6.low torque @ high rpm 12Nm@8500rpm>

7.low torque @ low rpm 12Nm@7500rpm Vs. 15Nm@8500rpm>
8.high torque @ high rpm 15Nm@8500rpm>

Similar cases with 3,4. Don't know if they are in production.


So, techies, experts, and experienced riders....
Pour in your explanations and experiences, so that one can get to know

1. What does these figures really mean?
2. What each of such configured engines are really meant for?
3. The feel of each type of configuration!
4. Pros and Cons of each type of configuration!

This may help a rider choose his bike as per the need, preferred style of riding and engine behavior, at-least me!

P.S
Bare me, the longest after-note you may have seen.
Am a novice with bikes, both in experience and knowledge vs. many geniuses and legends here.
I have googled a lot before posting this. With google, if i get answer for one of the above quoted four for a config. not the other three, so searched it with Xbhp.
Here, the knowledge on this part is scattered. Finding someone saying something at some thread and before we get to co-relate it with other reply, we forget the previous one..
So, asked this question.

Oops, forget to add this.
For anyone, who seems the compared engines, they can easily find out that it is YZFR15 and CBR150R. I have no other option but to chose these two as they are same .15L engines with contrasting engine figures. So, don't get into brands guys, just talk with the figures.
Of course, use brands when telling your experience and please let a biker's experience be his/her own and don't contradict it!

It will be nice to chat rather than to argue!
Please, correct me if I was wrong somewhere, and I would be happy to correct me!

Topic Merged.

@ neevarp16: All these topics have been discussed in one form or another. Kindly search the forum, and specially this topic... And seeing some power graphs may also clarify the doubts you have.

Awesome thread.. I had similar doubts...


My Signature

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One day, I will take it easy. Today won't be that day...
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Thanks for the approval!
and I was not aware such a topi existed in Pit stop, it didn't pop up in search too.

Anyways, a thread to follow!

what bike will have more top speed.?
when both bike are At same 10500 rpm what will happen.?
please explain.

Incomplete data. and it will remain incomplete until you try it practically.
you need more data, weight, gearing ratio, actual power transmitted to the rear wheel,size of tyres, compound of tyres being used, weight of rider, gear that the rider is wearing, aerodynamics(drag), clutch specification, etc.

Please understand..bikes these days are not just works of engineers. Its art. Since you cannot compare 2 drawings of different artists by just knowing what colors, brushes, canvas they are using - unless we have the 2 placed together, you cannot give data and calculate the performance on just that basis of 2 motorcycles as well. Considering performance, it is not that simple.

for clarification, Power is the rate of work being done. In simple words, if you place both these engines out of their respective chassis and then compare which one touches 10500rpm first, its most likely to be the 13.10ps one. But when it comes to top speed of the bikes, your talking about hundreds of pieces working together to achieve a particular result. So it becomes too complicated with just the data you have provided.

Considering Yamaha's Flagship R1 - 998cc,180bhp (Approx) and The Vmax - 1679cc,197bhp.
the R1 goes around 182mph while the Vmax goes 143mph. So you seen, there are hundreds of this that bring the result of less top speed of the Vmax. But the Vmax has enormous torque.
For eg. A 400kg weight tied to the R1 and to Vmax. The R1 will take more time to touch 100kmph compared to the Vmax. Because the Torque (force on the crank shaft) of the Vmax is way more than on the R1. So the R1's crankshaft will not rotate as fast with the load tied to it, compared to the Vmax.

consider most points are almost equivalent . then on..
1. what is the advantage of those additional cc yamaha sz-r 153cc has than discover 135cc.?
2. at 10500 rpm will speed increase or remain same by rated rpm of max power?
3. why yamaha sz-r will not have top speed.?

many many thanks for your simple english lines.

A bigger engine will produce higher torque at the same rpm(considering commuter engines)compared with a smaller engine.The extra cc's on the sz are useful in a way that you do not need to downshift gears a lot if you are at say 30kph in fourth gear and want to increase your speed.The same on the discover 135 you will get a bit of knocking while attempting the same.
(P.S. I have used the example scenarios just to explain the concept and the speeds vs in-gear characteristics are not real but just based on theoretical knowledge and practical knowledge gained from comparing RTR160 withRTR 180)

thanks vigesh and r-series brother. i m getting n learning.

i did some internet search, n found some good story. i am not sure whether this applies.

yamaha sz-r 153cc power (ps@ rpm) 12.1ps @ 7500rpm
discover 135cc power (ps@ rpm) 13.1 ps @ 8500rpm

in order to compare power factor
clearly sz-r is more powerful as it is able to generate more power at less rpm and more torque at less rpm. a 18cc extra helps in torque factor.

Re: What is "Power", what is "Torque"..??

Torque is the force with which the motor rotates, Power is the rate at which the energy from the motor is transferred. Power depends on the torque and the RPM of an engine. A given hp of power can be produced from infinite combinations of torque and rpm.

Horsepower / Torque [ On track difference ]

Hello,

I was watching some video on youtube where they were testing few naked bikes and one of the test rider said ' this track is not Horsepower favored but Torque favored so Aprillia is better than a Super Duke here ' .

I am still uncleared about the statement what does he mean by that ? . If anyone can clear the difference between HP/Torque in a general manner and what characteristics of the track made him say that .

Thanks