Jul 21, 2008

Yamaha R15: 17 bhp's too little, surely

So, it would appear that most of you were expecting the R15 to make in excess of 20 bhp. 54 per cent, to be precise. Hmm...

I did some checking, and here's what I found.

Fact 1: It's not impossible
Yes, a 150cc engine can easily make as much as 24 bhp. But there are specific conditions under which this can happen. Producing big power means burning big amounts of fuel, producing large amounts of exhaust gases and since the bangs are bigger, literally, making a heck of a lot more noise. Which means, you, the customer has to be willing to live with a rackety, polluting motorcycle. Which you may well think is fine, but the Government doesn't. India happens to have some of tightest norms in the business, especially noise norms, which means big bangs, much as we like them, are not on menu. In fact, the R15's motor, incredibly similar to the Indonesian V-Ixion's actually makes about 1 bhp less. Blame goes squarely to the norms.

Fact 2: You probably won't like it
While we all love to harp on and on about horsepower, the truth is bhp is not all its cracked up to be. Yes, that's a pretty strong statement, but hold on a minute and lemme explain.

First of all, horsepower doesn't exist, except as a mathematical function of torque. Dynos measure torque. Not horsepower. The dyno's computer calculates the horsepower and plots the curve we so love.

Second, it is torque that really thrills you. Despite all the claims to the contrary, not more than a fraction of a percent of enthusiast buyers actually use the full potential of their motorcycle. By that I mean riding up to the redline, repeatedly, daily, purely for the enjoyment of it. Which is the sole riding mode in which horsepower comes out to play. The rest of the time, all you're enjoying is the torque curve, playing with the peak and enjoying the satisfying surge that comes with opening the throttle.

Third, and most importantly, a 25 bhp 150cc, almost by definition must make its significant torque far up high in the rev band. Which means it will require a right thrashing to produce any sort of performance. Any time you want the bike to pick up its skirts and run hard, you're going to have to suspend all mechanical sympathy and whip the poor thing. No one can ride like that day after day. Even racers can't ride like that – it is simply too stressful!

But here's the thing. Would I have been happier if the motorcycle were making 25 bhp? You bet your, um, you know.

But I understand that it isn't possible, and from what the engine designer folks (and not just at Yamaha) are telling me, a genuine 25 bhp 150 wouldn't be a pocket rocket, it would be a ticking bomb. When you light the fuse, it would explode. And there'd be nothing in it before or after the event. Big explosions like that are fun. But too many of them, strung in a row get stressful, and eventually, you simply don't want any more. I was also checking on google and I found a couple of people who were upgrading their 19-odd bhp CBR150Rs to 25-odd bhp. But the interesting thing is that both were talking about having to install a 195cc kit to make the power reasonably useful.

All right, now I'm waiting for your comments.


theslayer said...

Finalllllly! Somebody gives me a convincing explanation!

"a genuine 25 bhp 150 wouldn't be a pocket rocket, it would be a ticking bomb"


Now coming back to the 150cc, why a 150cc when you already have a 250cc mill all over the third world nations waiting to be just plucked and plonked?

Not considering the talk about the test bikes on the track the other day being detuned, I was mighty disappointed when the R15 felt a tad slow compared to my 220. There is a huge difference in the way both beasts behave when revved up al the way in first gear. One is bliss, the other leaves us wanting.

Oh and... glad to have you back!

first_synn said...

You'd be wrong on one count. The V-Xion makes only 15 PS. It is also a world away from the R15 when it comes to specs and detailing.

End of the day, corners > strightline and this is where all the extra dough spent on the R15 over the competition starts to shine through.

P.S. Am I on some kind of comment ban or something? Been a while since I've seen you publish my comments, you know?

If there's any bad blood that I may have unwittingly caused, Here's what I propose. Next time you're here, Carlsberg's on me and let's talk this one through like men do.God willing, you may be able to enjoy an islandwide ride on something tasty too...

Anonymous said...

Sure, 17-ish bhp from a 150cc engine is all right. What I really want to know is, why the hell did Yamaha not launch a YZF R25, with a 250cc, 25bhp engine?

Now you'd probably say that a liquid-cooled 250 twin would have been too expensive for India and all that jazz. So, fine, make it an air-cooled 250 single, with 25bhp. Come on Yamaha, how hard acn that be?

A sharp 150, with race-bred chassis, suspension and handling would be fine if most buyers in our country were budding Rossis, with race tracks scattered all over the country, on which to max out the bike on weekends.

That, as we all know, is NOT the case. On our kind of roads and traffic, a 25bhp 250, even one that's not as technologically advanced as the YZF R15, would have been a better bike...


rearset said...

Comment ban? You? No way man. I do have a problem with blogger not sending me (apparently) all comment notices to my email address. I seem to get a few, and discover a few when I click on the blog's dashboard... but I can't remember blocking any of YOUR comments.

rearset said...

We're still on for the Carlsberg, despite the lack of the bad blood that seems to be required in the first place... B-)

first_synn said...

Let's put it this way: There's no bad time for Carlsberg. :-D

About the wheels part, I need to get your opinion on something. Will mail you later today.

Hitanshu said...

Very very interesting.

Which is why I now understand why I never found the pulsar 180 as quick as some of my friends claim it is (they stay upwards of 7k RPM lifelong). and why I still pine for the ZMA :)

Explains why my preference even in gaadis is for more lower torque than a rev-its-balls-off-to-fly approach.

Welcome back. In whichever way - you are now posting.

irondad said...

Torque, horsepower, whatever. All I care about is will the bike do what I want it to do? I laugh at bike buyers who agonize over tiny differences in the numbers. "My bike has more of ( fill in the blank ) than yours. I have no idea what it is and can't use it anyway, but it's there so somehow that makes me better than you".

Pocket rockets getting ready to explode just for a few horsepower hold no interest for me. Sorry.

EvolutioN said...

@ Rearset

Here's the deal...

On one hand you have the Horsepower, which more or less dictates the 'zippiness' in the machine, but comes into play only when you rev past the redline, and on the other hand, you have the Torque, which would ensure you hold the throttle wide open for 10 kms when your needle shows a 120 kmph without the wrist getting jerked to bits!

It all depends upon what style the rider adopts, if it is a 300 miles per day person, Iron Butt style, a 150 cc 25 bhp bike is not much good... as you say, it ACTUALLY would be simply too stressful... However, for normal everyday commuters, an 18 Nm Tbird is not much good either, simply because the bike struggles to hold out the throttle at lower lines...

Though I am one of the manys who wanted the R15 to be above 20 BhP, preferably around the 22 - 24 bhp mark, i am not too disappointed with the peak power performance... And on the road, the beast looks good... gotta give her that credit!

So critics be damned, my-bike-has-1-bhp-more be damned (a-la Irondad comment), this bike can open a can of whoopass, and how!



Sneh said...

I was a bit disappointed to read your post as i read it just after booking a Racing Blue R15. I got your point.
At the same time, as Evolution has said, riding style defines the choice of bike.
This tiny bike has more to offer than just BHP/ torque figures and I have strong feelings that power curve will be flatter than other 150cc rivals because of better volumetric efficiency (read 4 valves).
Correct me if i am wrong.

Julian said...

i got a question. let's say that the r15 costs Rs. 1 lakh.

how much more would it cost for it to be a 300cc twin cylinder? realistically, taking the forged piston and all the other hi-tech, expensive gadgetry into account.

Siddharth Soni said...

This piece is wonderfully worded. Thanks. Am not very intelligent when it comes to technical stuff in bikes. But I literally found comparing one bike to another on the basis of 'bhp' rather parochial. No less a motorcycle enthusiast, I would rather judge a bike based on a holistic experience and how it fits my temperament and purposes...

I couldn't test ride the R15 but took a pseudo test anyway. Seated myself on it, revved it, saw the needle move smoothly, noticed the muffled noise, judged the neatness of the design and got convinced that it's a nice piece of machinery. :)

Max said...


How could I miss the party, without meaning to ruffle any feathers here, may i ask WHY you are being so diplomatic about the R15?

Me and you (if I know you well!) and a lot of similar people ARE disappointed with the final outcome, yes 25 bhp may be a bit too much, but couldnt they do a genuine 20 (since we're talking +/-5 here) without ruining the curve?

Also, correct me if am wrong, but if a rider looks for the 'general ride' pottering about in mid range with some left over, then one would rather buy a Cruiser, or a Sports/Tourer, or even a roadster, but NOT something which is hailed (wrongly) as a 'performance sports bike'.

I was quite miffed at the lack of power, but in general am glad, it means that many lesser wannabes to contend with on the road going forward (its not that fast anyway)

And frankly, I speak for myself, and partly for you too, a genuine 150 bhp 150 is exactly what the doctor ordered, a pocket rocket, a ticking time bomb, a niche jewel, something worthy of respect. Instead, we get a glam doll with nice legs and bust but lousy staying power!

:-) and yes, How have you been?




rearset said...

Almost exactly double, maybe a slight bit under that...

Diplomatic? Um, that would not be the word i'd choose. I'd say something like 'soft' And I say that because the R15, despite the fact that the majority of us would like a lot more power, is actually a pretty sorted machine. Make that the most sorted machine we've ever got. I'm scared that more power would have created something like an FJR1300 - all engine. Or worse.

What I am saying is that I think the R15 is very interesting to ride at its current power level and the interplay and balance between the chassis, the engine and the rider is of an order we haven't seen yet. What I am saying that for most of us, who've been riding the pants of our P180s, Karizmas and what have you, the R15 has enough guts and ability to keep you enthralled for the 24-odd months it will take before the bigger multis turn up and blow your doors down. My gut says more power would ruin the friendly, encouraging nature of the R15 and turn into a motorcycle that a few will adore, fewer will ride to the limit, and leave a lot of highly charged enthusiastic but new riders out in the cold. At the moment, the bike has more than enough for everybody to join in the feast. That's the big reason.

The other reason, is that I wanted to make sure everyone knows what I found out – that in our emission scenario, you can't make more than 17 bhp. And this is not a statement that came from Yamaha, but a rival company who tried very hard to squeeze more from an on-test 150cc motor and failed. The exact statement (pre R15 launch), I believe was, 'If Yamaha can launch the bike more than 17 bhp, then we have something to learn about the basic internal combustion engineering from them.'

A 150bhp 150? Bring it on. Just leave the delicately poised R15 alone, until I've gotten thoroughly bored with it. Is all I ask.

Answer your question?

Payeng said...

Auto Mags are more responsible than anyone else for raising the expectation sky high with figures like 20-22 BHP (right after the Auto Expo 2008) for the R15.

Vivek Singh said...

Hello, I am a Tech Specialist in a MNC in Noida and a great bike lover, I am riding since the age of 9 and I am 29 today.
I have completed 4000 Kms on R15 and using it since a month.
I totally agree that when I first made up my mind to go for it, I thought it must be a something more powerful (when it comes to pickup).
But I would really say that its far more better than any other Indian Bike in the market.
Having used both Karizma and Pulsar .
And I will like to share my outlook;
1. I have travelled straight from Lucknow to Delhi having only two stays in between thats about 200 kms of non stop riding at a speed of 75-80 on avg. (coz of its Diasil cylinder and Forged piston, cilinder has 20% silicon which keeps it cooler than rest of the bykes.)
I dont think any other Indian Byke can do that, it will burn out and the clutch plates will cease.

2. It has given me amileage of 45 km/lt on highways and 38-40 kms/lts in City.I n which I have operated it around to 135 km/hr at times.Which means Its best in its class.
3. It has an awesome grip on roads, its not important for a bike that it goes past 130-140 what is important its that how much safer it is to go to that speed. Toy can really feel safe at speeds of 120, the byke will not skid when applying brakes as that speed.
Some people say that it has narow tyres, they were specially made for R15, having soft rubber and different raddi, complete tubeless providing 3 times better grip that Pulsar and about 2 times better that Karizma in my view.
Before riding this I loved Karizma, coz it was better than Pulsar, but those two feel to be pieces of srap of primitive machines when comapred to R15.
Dont check the speed and pickup. Ride it above 120 km/hr you will forget about the price and comparisons.

Payeng said...

@ Vivek Singh..

Just for the record.. my brother rode around 2500-3000 kms, with a pillion, at average speeds of 100+ Kmph.. in a single road trip all the way from Bangalore to Gurgaon just to transport my Pulsar 220 and deliver it to me..

I am sure that the Japanese bikes are good.. and can certainly teach the Indian bike makers a thing or two.. but the Indian bikes from TVS and Bajaj aren't that bad either.

EvolutioN said...

:)(wrt Vivek's post...)

am not out to prove a point... but have ridden from hyderabad to Hampi (498 kms) with only 2 major pitstops with an average of 75-80 + kmph for 2 - 2 1/2 hours (you have to realise that to do that average, you have to ride at a 100 + for about 20 - 30 kms somewhere in between)... And mine was a stock Apache... So dude... while i realise you are all ga-ga over the R15 (I am too, by the way), I dont think its fair putting down other tried and tested bikes on the road like that...

And dude... how did you measure that the grip of the bike (mind you, the bike, not the tyres :D) was 3 (woo hoo!) times better than Pulsar and 2 (~yeeay!~) times better than the zma? Where did the numbers come from? :)

Good read! a much needed dose of humour early on a drab thursday morning... :)



EvolutioN said...


I see Satadal is earlier to the post! woo hoo!

all smiles



Revhard said...

So if 17PS ( 113.3PS/litre) is the max they can get while meeting emission norms, how is the R-1 getting 175PS ( 175PS/litre )?

Or do the import rules not require imports to meet emission norms applied to bikes manufactured within India ?

rearset said...

My friend, you forget that for the same set of emissions, a four-cylinder motor should be able to (and does) produce more power. And consume more fuel too...

first_synn said...

Also, it matters that bikes over 800CC are not required to conform to the emission norms set for our more mundane two wheelers.

Instead, they follow the guidelines set for cars. Which are much less restrictive.

Revhard said...

Alright, then put together 4 R-15 engines to make it 600cc , total power = 68PS ( if you actually combined 4 such engines into a single, the total power should be more since some savings in weight/mechanism come by way of common crank & cam shaft etc ).

Er, the R-6 makes 125PS+ from its 600cc ( higher compression and revs using more peaky cams etc). So it does seem like European/US emission norms are less stringent , else that would cap the R-6 to 75-80PS too, assuming same level of combustion & emission control tech used. So Synner may well be right about imports not being required to meet Indian emission norms. If not, we are being passed up again ...

rearset said...

Again. I still do not understand why everyone assumes that Europe, or indeed California, has the tightest emissions on the planet. Actually, we do. Our noise emission norms, especially, are tighter and yes, First Synn may be right about the imports not needing to meet the same emission norms (the logic is that sales volumes are too low to make a big impact).

Also, adding four singles will never give you mathematically totted up power, or thereabouts. Four cylinders working together produce a heck of a lot more power than the equivalents of four singles working together.

The explanation is complicated, but the upshot is that in the turn of a crank (360 degrees) more than one combustion event can occur... I think... this is from memory, will have to check it out for the exact answer. But yes. Splitting a 120 bhp four into singles wont give you four 30 bhp singles. And adding up 30 bhp singles wont give you a 120 bhp single either.

first_synn said...


Like rearset mentioned, it's not as simple as 4*A=B.

For starters, the R15 uses an SOHC Head (The R6 has a DOHC one). It has lower compression. One less intake valve. A MUCH simpler engine management system. No exotica inside to lower frictional losses. And so on.

Also, lets not forget that a 4-banger inherits a much higher momentum due to the additional moving parts, and therefore(Theoretically) can do work at a faster rate than four isolated single pots. (Techies, correct me if I'm wrong on this one).

Lastly, more cyls=higher rev ceiling=higher chances of extracting more power.

vibhu said...

Its not just the bhp figures ...

A colleague got convinced that he would buy the R15. So, he went, checked it out, went to the HH showroom next doors and booked the Hunk !

I was shocked - and asked him why not the R15 ? He said :

"It looks puny."

Now, seeing them on the roads , i have to agree with him. From near, you can inspect the finesse of the work done, but from a distance - the bike looks like those fairing jobs done on cbzs to make them look like a cbr.

GR said...

I dont think any other Indian Byke can do that, it will burn out and the clutch plates will cease

ummm I guess you meant the engine will seize and the clutch plates burn out.

if so no

some time back 435 km to Hampi from Hyderabad, break free. took me about 8 hours.

This was the carefully picked out "scenic" route, but I am sure i did much more than 2 hours n/s at 80 or higher) nothing happened

and i got back without falling into canals thank you ;P that was on the 220

500 km in a riding day is kinda routine at the office na, not exactly some diabolical torture test but rather something which i (and undoubtedly many others here) have done umpteen times on all kinds of Indian/ bharatiya bikes without trouble.

of the pizza engine/ papad clutch kind

Oh and

Obviously with something like an engine, you would have to use a verb that doesn't have an abstract subject.


Revhard said...

Synner, you missed the point I wuz making . Emission norms aside, there's a huge gap bewteen 113PS per litre and ~184PS/litre that the R1 makes. What Rearset points to is ridability ( ie torque spread ) and emission norms being responsible for this.

That's only part of the story , which is why I brought up the R6 with 600cc 4 cylinder comparison with R-15 x 4 block . I know too well the SOHC and long stroke ( 58.7mm stroke , bore is 57mm , even Unicorn is shorter stroked) isn't the bleedind edge tech like the R6 is . End of the day, Yammie picked up what they alreay had elsewhere in Asia , jazzed it up with fairings an uprated the motor to 17PS to make it sportier , but this is merely reselling old wine mixed with some new wine in a new bottle.

There are some folk who've joined up 2 500cc Bullet engines to make a ~70bhp (IIRC) 1000cc V twin Bullet , that's much more than the 24bhp 500c ( 48bhp/litre ) of the Bullet 500. Extracting more power from a higher tech engine like R-15s wil be harder, but no doubt a hybrid 4x150 should make over 68bhp since total pumping losses should be lower. But 68PS from 600cc and 120+PS from 600cc is a huge gap. Thats the missing link is large specific power - it's actually still not cutting edge.

A larger 250cc in lower state of tune would be much more rideable at little increase in cost, but Yamah chose to sell an existing product from Indonesia, but still trying to sell it as a high tech mini-R1 . It sure is more advanced than P220 and Karizma et all, but not R-1 level.

Looking at bhp per rupee , R-15 is more expensive than R-1 if you discount the high import duty.

first_synn said...

Revhard: It is quite unfair to call the R15 a "picked it up from elsewhere" bike. The V-Ixion platform is only a couple of years old and the donor bike is a world away from the R15 when it comes to detailing. The R15 engine's bottom end is shared with the R125 of Europe, actually (Yamaha's words, not mine).

About the mating of four single pot engines, I think Rearset and I have explained how and why more cylinders/ engine can help extracting a higher power output.

As far as pricing goes, let me assure you. There is not one bike in the world that offers as much equipment as the R15 for a similar price. If you wanna look at it mathematically, fine. But sometimes, the sum is indeed greater than the parts. :-)

axl said...

Dear revhard,

ride the bike and see. i think you'll find that its worth its price tag.

With regards.

EvolutioN said...

@ gr

kindly make your profile available... would love to read more on your blog... you seem interesting!

@ rearset

certainly not a newbie to riding, but a newbie when it comes to understanding the hardcore technical portions of the dialogue going on above... Could you suggest some reading material?



Tandeep said...

brilliant.. finally someone else who thinks that torque is the one doing all the torquing ;-) a neat article.. i still haven't ridden the r15 yet, but wat i hear from most ppl who have, plus mag articles, u really need to keep it on the boil to feel it move.. the max torque comes in at around 6500 rpm and its an undersquare engine to help it develop more of the torquey feel lower down in the revs.. i believe they gonna fine tune n tweak it a bit more so tat it develops torque at lower revs.. this is beside the point.. since the r15 looks, feels and rides like a sportsbike.. n most of them are the balls out-rev it till it breaks type of machine..

yamaha how about fitting the same engine in the fz15 with the required tweaks for a more torquey engine.. but again kudos to yamaha for taking a bold step.. jus wish they sort out some of their pathetic dealers..

Different League said...

I loved my ride on the R15. feedback , road grip , handling , brakes and fit and finish are on a whole new level. no pulsar , karizma or RTR can even hold a candle to it in these aspects. yes the bike could be a lot more powerful but IMO 17bhp coupled with its phenomenal feedback and handling will actually make the R15 the easier bike to ride in real world street conditions then say a ported 25bhp 135cc RX135 .