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Old 28th September 2015, 17:24   #16
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Default Re: 2014 Honda CBR650F And CB650F Unveiled

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Originally Posted by Porschefire View Post
Mate, I hope you do realize that there are many more 'human beings' in this world apart from you? While you may be happy with 20-30PS, there are many others who aren't content with even 200-300PS and thank god for them that we have machines like these available for the mango people like us. If the homo sapiens weren't a curious folk, we'd still be walking to places today.
Yes, I do realize that this is a wish from a customer segment. My question was not meant to offend you. I have no reason to object if some consumers wish this.

It is a technical question. The high power engine (like 200 BHP) gives you higher torque at the wheel. But 200 kg gross weight (bike + rider) is not sufficient to take that torque without slipping at the tyres. And after getting into motion, there is not so much resistance to overcome (like rolling resistance or wind resistance) as to need 200 BHP.

As you said, it seems to be just a matter of 'happy state of the mind' to take pride about 200 BHP. In all probability, the bike manufacturers triggered this sense of pride for their business promotion.

I do understand that everyone is not equal. By any means, I am not criticizing you or the people who buy or like such bikes.

Last edited by Rahul Bhalgat : 28th September 2015 at 17:28.
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Old 28th September 2015, 18:22   #17
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Default Re: 2014 Honda CBR650F And CB650F Unveiled

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Originally Posted by Rahul Bhalgat View Post
I am curious to know why do the manufacturers provide such high power?
Because consumers want and manufacturers can. Also, evolution !

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Originally Posted by Rahul Bhalgat View Post
But is 20-30 HP not sufficient for providing the a pick-up that a human being can handle and sustain?
Even 1 HP can be handled and sustained by a human. So can 200 HP, depending on the skill set of the 'human' in question. Why this special range '20-30' HP ?

Quote:
Originally Posted by Rahul Bhalgat View Post
It is a technical question. The high power engine (like 200 BHP) gives you higher torque at the wheel. But 200 kg gross weight (bike + rider) is not sufficient to take that torque without slipping at the tyres. And after getting into motion, there is not so much resistance to overcome (like rolling resistance or wind resistance) as to need 200 BHP.
Its not like its slipping with zero efficiency with the horses beyond '20-30' hp.
The faster you run, more the opposing frictional force that one will experience. Does that mean Bolt stops running over a particular speed ?

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Originally Posted by Rahul Bhalgat View Post
As you said, it seems to be just a matter of 'happy state of the mind' to take pride about 200 BHP. In all probability, the bike manufacturers triggered this sense of pride for their business promotion.
None of it is true in my opinion and I can have an opinion too.


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Originally Posted by Rahul Bhalgat View Post
I do understand that everyone is not equal. By any means, I am not criticizing you or the people who buy or like such bikes.
I thought you were feeling curious about why makers pump in so many horses in spite of the fact, for you, that human can sustain only '20-30' HP !
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Old 28th September 2015, 18:24   #18
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Default Re: 2014 Honda CBR650F And CB650F Unveiled

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Originally Posted by Rahul Bhalgat View Post
Yes, I do realize that this is a wish from a customer segment. My question was not meant to offend you. I have no reason to object if some consumers wish this.

It is a technical question. The high power engine (like 200 BHP) gives you higher torque at the wheel. But 200 kg gross weight (bike + rider) is not sufficient to take that torque without slipping at the tyres. And after getting into motion, there is not so much resistance to overcome (like rolling resistance or wind resistance) as to need 200 BHP.

As you said, it seems to be just a matter of 'happy state of the mind' to take pride about 200 BHP. In all probability, the bike manufacturers triggered this sense of pride for their business promotion.

I do understand that everyone is not equal. By any means, I am not criticizing you or the people who buy or like such bikes.

I Logged in specially to answer you.
You surely are not familiar with bikes and how they produce, manage and transfer the power to rear wheel.
having less weight is an advantage rather then a negative. The better the power to weight ratio, the better the performance.
I hope you understand how torque is transfered and slipping of tyres as in your words does not happen because of this. It happens because the person riding the bike does not know how to launch the bike without skidding the tyres.
Rolling resistance/wind resistance: These bikes are not made in local garage. they are developed in the state of art factories with wind tunnel testing facilities.
Also I can explain all the gadgetry and the high level of equipments available in bikes but that might confuse you more.

In short my friend: Bikes are really capable of handling such power figures.
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Old 28th September 2015, 21:17   #19
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Default Re: 2014 Honda CBR650F And CB650F Unveiled

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Originally Posted by mandhir.s.bajwa View Post
I Logged in specially to answer you.
You surely are not familiar with bikes and how they produce, manage and transfer the power to rear wheel.
having less weight is an advantage rather then a negative. The better the power to weight ratio, the better the performance.

Rolling resistance/wind resistance: These bikes are not made in local garage. they are developed in the state of art factories with wind tunnel testing facilities.

In short my friend: Bikes are really capable of handling such power figures.
Appreciate your elaborate reply.

First of all, I had made it clear that mine is a technical opinion. So please do not get into personal comments like "You are surely not familiar with bikes". Please do not be in a hurry to pass on a judgement on my knowledge. This forum does not expect this. Any personal comments will have to be reported to the moderators.

For your information, I am an engineer, a mechanical engineer. And that too a practicing engineer, been into engineering throughout, with long experience. Being a true engineer, I am open to accepting and learning if my comment is technically incorrect.

Let us talk technically:

Lighter weight of the bike:
  • To move on the ground, the bike tyre needs to push the road towards the rear.
  • While starting from rest, there is a certain maximum amount of push a bike can generate without slipping the tyre. This amount of push depends upon the bike weight, the nature of road surface and the nature of tyre material.
  • To generate this push in the first gear, you need certain torque at wheel that is generated by magnifying the engine torque through the power train. More torque than this does not produce any additional acceleration for given road and given tyre material.
  • In other words, better the power to weight ratio, better the acceleration but there is an upper limit to this acceleration, which is determined by the bike weight and the nature of tyre and road surfaces.

Rolling resistance / wind resistance
  • When you say "These bikes are not made in local garage. they are developed in the state of art factories with wind tunnel testing facilities", I interpret that these bikes have lower wind resistance and lower rolling resistance compared to ordinary bikes.
  • Having less weight also gives an advantage, as you said. This advantage is : lower rolling resistance.
  • So, if there is less resistance to the motion (compared to normal bikes), what is the reason for very high power and high torque?

Being an engineer, I am really open to learn if something is missing in the above explanation. So if you have logical and technical explanation to justify 200 BHP for 200 kg (of bike + rider), I am open to consider.

Let us not treat this as a challenge or an argument. Let is be an exchange of technical views and learning. I got into this matter purely my first feel as an engineer said 100 - 200 HP, 4-cylinder engine for a bike is disproportionate and redundant.

I am also sending a PM to few professors and automobile designers on this forum and requesting their participation in this discussion. FYI, I design machines. Recently, I had to a add a substantial amount of dead-weight to a hauling device (a sort of locomotive designed to work indoor on rails, hauling 320 ton bogie). This was done purely to avoid the locomotive wheels from slipping.

Last edited by Rahul Bhalgat : 28th September 2015 at 21:23.
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Old 28th September 2015, 21:20   #20
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Default Re: Honda CBR 650F launched in India at Rs. 7.3 lakh

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Originally Posted by Rahul Bhalgat View Post
650 CC, 4-cylinder engine with 86 BHP for a bike!
Is there any cap (upper limit) on the CC or HP of a motorcycle in India?
There is as such no cap on power or capacity for motorcycle or cars sold anywhere.
There are some licensing restrictions in the US and maybe Europe where certain license holders cannot ride a motorcycle greater than certain power.

This is also one of the reasons CBR650F produces slightly less power than other 650 inline 4 motorcycles. In US A2 licenses restrict the riders to below 50 HP plus a motorcycle cannot be detuned to 50% of its original HP for A2 license hence CBR650F was meant to be below 90 BHPs.

The only other similar thing that I know of is that most motorcycle manufacturers have kind of agreed on an agreement that their regular production motorcycle in stock form wouldn't do more than 300 KMPH.

There is never going to be any Horse Power figure that will be enough for people. From 1000 BHP production cars to 200 BHP motorcycle, we always would want more power. Is it required or does it make sense is a very debatable concept. There are pros and cons of everything.

Rachit

Last edited by Gannu_1 : 29th September 2015 at 08:32.
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Old 28th September 2015, 21:32   #21
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Default Re: Honda CBR 650F launched in India at Rs. 7.3 lakh

@Rahul:
Thanks for the elaborated reply and good to know that you are into mechanical engineering. all the best.
And second: It was not a personal attack. apologies if it sounded like that.
Now lets come to bikes.

as you stated about bikes having 20-30 hp and how bikes having 200hp can be an issue. specially related to wheel spinning. And If I say that these bike are well equipped to handle such power figures then I speak from my experience. I have tried my hands on almost all superbikes available in India and can say that they handle much better then lower spec bikes. All because the kind of research and testing which goes into it. I talked about wind tunnel testing because this helps in aerodynamics to withstand windblasts and it aids in stability at higher speeds.
Also it mostly depends on the rider as how well he understands his machine and how much he respects the power. I have seen people doing huge blunders on 10hp bikes and have seen people meeting accidents because they could not handle 20-30 ps power. I'm short on time right now. But if you want technical details then we can talk over PM.
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Old 28th September 2015, 22:53   #22
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Default Re: Different bikes = Different riding styles!

Over the years i have extensively ridden 4 bikes
2011 Yamaha Fazer, 2011 RE Thunderbird 350, 2014 RE Classic 500 Desert Storm, 2015 Bajaj Pulsar AS200

Alas i have commuted really less in any bike, preferring to cycle around in city distances.

Yamaha Fazer
This is a very capable and reliable mini touring machine. Comfortable saddle, wideish handlebar, wide tyres and decent torque. It is good to ride even at the redline all day long. This was the bike i started touring on, and instantly loved it. It belonged to a friend from my student days and he rarely rode it. I borrowed it from him and did minor repairs and kept for a few months. Realised my love for touring on this bike and that prompted me to buy my first bike, a second hand 2011 RE Thunderbird 350.

RE Thunderbird 350
My first bike, my second love (my first love would kill me if she is reading this). Nice torque down the rev range makes it a relaxed highway cruiser. The ergonomics are just spot on. My highest distance in a day has been close to 600 km and i did not feel a little bit of tiredness at all. The single piece seat on that bike was a gem and the luggage tied to the back seat often provided good back support... . The only issue i had with the bike was its low cruising speeds. Anything above 95 kmph and you are rattled to the bone. Well, the lack of cruising speed eventually led me to sell this in favour of pulsar AS200. I would definitely have loved to keep this one, but a student always has those constraints.

RE Classic 500 Desert Storm
At low speeds and in second gear, ask your pillion to hold on tight. Cause he or she may fall off at a twitch of your right wrist. 41 Nm of torque is awaiting to furiously blow your mind away. My friend bought this one into our then enfield family. We all loved it and rode many a miles together. The torquy motor proved to be a heavenly tourers delight. And the dynamics are good enough not to let u notice the weight. In fact, i have had loads of fun cutting through traffic on this one, the torque being too much fun of course. The only spoilsport is its flat single seat. Classy as it may look, it is simply too painful on long rides. Try as i might, i never coukd do more than 100 km in a single stretch. It is a great companion on those slow and peaceful solo rides.

Bajaj Pulsar AS200
After my tryst with the Thunderbird, i was looking for a good bike to tour on, which also could carry a bit of speed. Well i did consider duke 390 and benelli tnt 300. Duke was too sporty and tnt 300 too expensive. Enter AS200 in april 2015, I decided that i would skip the upgrade now and move on straight to a 650 cc or higher. I bought AS200 in may from among its first production lot. Though i meant it as a temporary ride, i have come to love it over the last 5000 km. It looks gorgeous with that half fairing and has decent power figures. It doesnt throw u off, nor is it sluggish. The windshield hrlps in touring and the suspension is surprisingly pliant. I love the proportions and the right weight. It is a very versatile bike that suit all your needs - commuting, touring, mildly aggressive cornering, etc...
It simply hates having a pillion on board. It is best ridden alone.
Of course, it is not as comportable as my thunderbird but it makes thundering through those highways that much easier. I would definitely never sell off this one when i upgrade. I guess it is ok if i couldn't hold on to my second love, but i ll hold on to my third love.


Apart from these, i have had short stints with platina, splendor+, super splendor, caliber 115, twister, etc. These are strictly average but reliable commuters. I have never really distinguished between any ride when i m commuting. I feel such short distances are simply not enough for me to pass any judgement, so i chose to reserve mine.


Thanks to Navin for this wonderful thread. Gives nice insights to others' experiences amd also serves as a short summary of many bikes...
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Old 28th September 2015, 23:01   #23
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Default Re: 2014 Honda CBR650F And CB650F Unveiled

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Originally Posted by Rahul Bhalgat View Post

Being an engineer, I am really open to learn if something is missing in the above explanation. So if you have logical and technical explanation to justify 200 BHP for 200 kg (of bike + rider), I am open to consider.

Let us not treat this as a challenge or an argument. Let is be an exchange of technical views and learning. I got into this matter purely my first feel as an engineer said 100 - 200 HP, 4-cylinder engine for a bike is disproportionate and redundant.
Are you serious? You're a mechanical engineer, but aren't you aware that such bikes exist? And they are ridden to their limit, and then some in professional racing events like Motogp etc? Those bikes have around 240 bhp and weigh around 150kg. Powerful bikes exist, and they work as intended. Apart from this, there are specialised bikes that are raced on salt flats in Bonneville, USA that set land speed records. In my opinion this is a silly discussion. This isn't theoretical. These bikes exist. You fail to account for technology such as good tires and suspension etc. Do a little research sir.

You say you are an engineer, yet you do not understand the purpose of having higher displacement and multiple cylinders. This is why people assume you do not know about bikes, because there's a lot more to modern bikes than the cylinders and cc. Your entire point of slippage etc is most because these bikes exist and function appropriately.

Also, most people are probably annoyed by the 20-30HP comment because that is reflective of the sorry state of Indian biking scene. Doubt it's directed at you personally.

Last edited by KhalDrogo : 28th September 2015 at 23:06.
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Old 29th September 2015, 01:02   #24
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Originally Posted by mandhir.s.bajwa View Post
@Rahul:
I'm short on time right now. But if you want technical details then we can talk over PM.
Sure, it will be a good idea.

I may be visiting Delhi next month, for a week or so. If possible, I will try to meet you personally for an hour or so. This will make a better interaction.

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Originally Posted by KhalDrogo View Post
You say you are an engineer, yet you do not understand the purpose of having higher displacement and multiple cylinders. This is why people assume you do not know about bikes, because there's a lot more to modern bikes than the cylinders and cc. Your entire point of slippage etc is most because these bikes exist and function appropriately.
Well, I know the purpose of having higher displacement and multiple cylinders.

Instead of saying that I do not know, let the discussion be about "is this much power really needed" and about "is 200 HP engine really needed for 150 kg bike even considering weekend sport riding?"

I read that you are from Panjim. In case, you happen to visit Pune or Mumbai, please let me know. I will try to take time out to meet and understand this. On an average, once a year I happen to visit Goa (Mapusa) for business purpose. Will inform you if I visit in near future.

Once again: we are all fellow members of this forum; instead of criticizing let us learn. I have no intentions to offend anyone. If I am not convinced for the need for 200 BHP for a 150 kg bike, please do not get angry.

Last edited by Gannu_1 : 29th September 2015 at 08:31. Reason: Back to back posts merged. Please edit your post within the 30 minute edit window to add/edit your posts.
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Old 29th September 2015, 03:11   #25
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Default Re: 2014 Honda CBR650F And CB650F Unveiled

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Originally Posted by Rahul Bhalgat View Post
I see....

I am curious to know why do the manufacturers provide such high power? Higher power and torque will result into quicker pick-up and speed. But is 20-30 HP not sufficient for providing the a pick-up that a human being can handle and sustain? After all the laden weight of such bike would be around 200 kg only.
Sorry for the OT, but you, sir, are using your mind when asking this question and the answers you get are from those using their heart. Total disconnect.

It's not about need , it's about want.
No one really "needs" 200hp motorcycles, but some of us utterly "want" them. A 20hp motorcycle will get you from A to B in nearly the same time as a 200hp motorcycle considering traffic and speed limits over short trips at least. But for the few seconds/minutes when you have the throttle open, accelerating hard, speedometer spinning numbers like a roulette wheel, those few seconds are bliss. It's the thrill of riding something that quick, that fast that draws some of slo-mo sapiens to them, despite nature not intending us to breach 40km/h.

As said in Hindi , "chalao to jaano" ( Ride it to know/experience it).

And some of us are very adept at handling and sustaining that sort of acceleration/speed for minutes, even hours. So adept, we even have competitive events to weed out the best, quickest, fastest of the lot.

Last edited by Ricci : 29th September 2015 at 03:14.
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Old 29th September 2015, 10:29   #26
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Default Re: 2014 Honda CBR650F And CB650F Unveiled

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Originally Posted by Rahul Bhalgat View Post
The high power engine (like 200 BHP) gives you higher torque at the wheel. But 200 kg gross weight (bike + rider) is not sufficient to take that torque without slipping at the tyres.
200 bhp is not the power we get at standstill. These high powered engines often have their peak torque coming in at higher rpms. So, at stanstill, we actually do not have too much torque (But it is still enough to spin the wheels)


Quote:
And after getting into motion, there is not so much resistance to overcome (like rolling resistance or wind resistance) as to need 200 BHP.
All the 200 hp of power is used to overcome the wind resistance at higher speeds (say 200 kmph). One does not feel any kind of wind resistance till 80 kmph or so. But rise a little above 120 kmph and the resistance is really the biggest obstacle. And at higher speeds, all that 200 hp is still usable because we have a great deal of normal reaction at the driven wheel because of the downforce. So yeah, all that power does come in useful when you are driving at 200 kmph, not by virtue of the laden weight but by virtue of the downforce generated by the aerodynamic design of the vehicle.

For a fact, F1 drivers experience forces close to 5 Gs. This directly translates to the wheels providing frictional force 5 times the mass of the car. All this is because of downforce and of course, the compound of the tyre.
Another point is, the tyre is not a rigid body,hence it is not governed by conventional law of friction which says the frictional force cannot be more than normal reaction in any case. It actually can be more in case of soft bodies in contact. Will require to study that extensively myself. Lost touch with that subject.
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