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Yamaha R15s vs YZF R15 v2 vs YZF R15 v1. The truth of R15s.

Posted on - 13 August, 2016 . Author - JT Ripper

Could an internationally acclaimed Automobile Giant such as Yamaha turn the most loyal fanatic/fanboy into a heartbroken skeptical? Read on to decide for yourself. *Spoiler alert* “The new R15s is not what everyone is assuming it to be”. The legendary Yamaha YZF R15 version 1 launched into 2008 in India, is a household name for various reasons. The masses know it for the pure superbike looks at an affordable price, an absolute head-turner with impeccable paint job and components oozing premium quality from head to toe. An instant status upgrade in the society if you will.
the lithe and sexy r15 v1
The motorcycling enthusiasts on the other hand, revered it for being the first true ultra-lightweight performance oriented engineering marvel. R15 bought many desirable firsts in the Indian biking scene – Diasil cylinders, Forged aluminum Pistons, Four valves, Liquid Cooling, Fuel Injection, Ultra lightweight and stiff racing spec Deltabox chassis, linked monoshock, and the overdrive of 6th gear on a 150cc machine. Now, Yamaha has built R15 from the ground up and the culmination of engineering perfection into each component resulted into a game-changing, mind-boggling, and earth shattering motorbike (for Indian biking scene).

Let me briefly delve into the technical details a bit for better appreciation of what made R15 v1 this Great. Diasil is a 20% silicon alloy of aluminum, ultra-light, with excellent heat dissipation properties (3.1 times more than iron), and with special surface coating there was minimal friction between piston and cylinders, hence lesser wear and longer engine life ergo the engine didn’t lose power/performance even after years of redline thrashing. Forging imparts aluminum with immense rigidity while retaining the lightweight character, so the forged aluminum pistons could easily cope up with the high compression ratio environment hence better suited for high pressure conditions.

The biggest benefit though, performance wise was the lighter reciprocating mass which meant it shoots towards the redline of 10k as enthusiastically as a monkey on cocaine. Force = Mass x Acceleration; so lighter the mass, less force is needed to accelerate them also they accelerate faster than conventional piston/cylinder arrangements anywhere in the rev range. This also means even BEYOND the redline, the engine would keep on producing power for there is lesser counter forces due to lesser reciprocating mass! Forged aluminium pistons are used in superbikes for this very reason.
diasil cylinder explained
Four valves means the engine never lacks air or fuel to breathe in and there is ample room to expel the exhausts completely. A better breathing engine is a happy engine which likes to revs freely and cleanly without throwing hissy fits or screaming in agony like most two-valve engines do. Liquid cooling (an aluminium unit as well) kept the vibrations, noise and knocking issues at bay and even after a whole day of abuse the engine kept it’s cool and was ready to push further. The ECU mapping for the fuel injection on the v1 was perfect, the torque curve was very even and smooth and the power curve was linear but aggressively steep as the RPM’s climbed farther, characteristically similar to an inline-four. Though, the stock ecu limited the engine to 10k for relaibility, guys who experimented with piggyback ECU's and race spec cams getting their engines to rev till 12k were richly rewarded. This video is one fine exmaple, easily doing 150 km/h in traffic. Pay attention to how cleanly it revs, such tractability.

I still vividly remember the first time I rode one in 2012, the almost silent engine made a swirling induction noise when full throttle was applied, the way it picked pace was a newfound territory for me coming from pulsars and CBZs. How cleanly it pulls through the rev range in every gear and even more admirable was the power delivery which kept on escalating, there were no weak or flat spots. Such clean fuel maps provide a ride-by-wire esque throttle response. Even more eye opening was the samurai sword like sharpness and precision of the steering, wish I had an action cam back then to capture those glorious moments.

The stiff chassis (read phenomenal feedback) with such a short wheelbase and aggressive rake + trail combo gave R15 v1 unprecedented steering response. It was a revelation for Indian bikers coming from squishy commuters. Even the minutest steering input, no wait, even the slightest hint of an urge to steer made the R15 change directions instantly, it was almost telepathic. The effect was so dramatic for us Indians accustomed to wrestling with handlebars for maneuverability that most first time riders were taken aback. In an ironic way Indians blamed the sticky but narrow rear tires for this apparent “instability”. Coupled with our lifelong experience with low quality “budget” engines habitually making us shift at 4-5k rpms didn’t let the uninitiated riders exploit the true strengths of the R15 v1.

And then there were immensely potent brakes. Even with a pillion, doing stoppies came naturally. Ridiculously strong bite and supreme feedback. I don’t know how they managed but the front end was remarkably less prone to diving on hard braking than version 2. The lighter weight and 50/50 weight distribution is the reason maybe. We’re living in a Spec one-upmanship era where immature riders only compare bikes on paper. Bhp or say power/weight ratio wars are fueling the Indian biking scene. What they don’t realize is numbers are only numbers, motorcycling is about how each component contributes towards the whole riding experience and in that regard, r15 v1 was, is and will be a true Legend.

Indians being Indian, putting form over function demanded a “bigger bike look”. Looks are paramount, full fairing and fat tires even on a 50cc machine would be a big hit, not even exaggerating. So Yamaha complied and added length, weight, fatter tires and even more “superbike” looks with that R6 tail section in the V2. Indians wanted “pickup” as well, in India acceleration means how much torque the engine has in the 2k-5k range, forget mid or top end. Hellishly congested streets, obsession with mileage and “save engine by not revving” paradigms are the real reasons behind that mentality. Yamaha said we feel you mafakas and remapped the ecu. Everyone was happy? Not really.
the hottest 150cc ever r15v2 blue
It surely had a bigger street appeal and pulled more enthusiastically in stop-go traffic but there were trade-offs. Most reputable internet resources pointed out these tradeoffs in a hush hush way but no one blurted out blatantly that the true essence of r15 v1 is lost. Added weight, wheelbase and fatter tires made the v2 less sharp. It was not as eager to turn, the flickability really took a hit. There was sure straight line “stability” now but who rides an ultra-lightweight mini pocket rocket for straight line stability ffs, go buy a cruiser or stick with your commuters. Even the top end of the engine took a hit, to extract torque down below the top end had to be sacrificed. Not by much but still, every rider worth their salt felt that on their butt dynos. The engine now started losing steam after 8.5k. This was only "felt", apparently the V2 is as fast or faster than V1 as per the esteemed online experts.

So a more practical engine (read less fun to redline) on a more sedated motorcycle ( read engine not powerful enough to exploit the new chassis geometry ) with much much sharper looks and ergos. Sounds illogical, ain’t it? I for one am a purist. In 2012 I wanted to sell my hh Hunk and get the r15 v1 but they discontinued it. I was not satisfied with the v2, the real deal breaker was that split seat to be honest. I’m an old school nigga, I want my ladies to sit in comfort and closer to me, not on another “level” with butt cheeks on display on that narrow joke of a pillion seat. So I shelved my plans to buy this one but secretly hoped they would re-launch the r15 v1 with a 200cc single cylinder engine. A R20?

Fast forward 4 years, the time is now and Yamaha has two more yzf options, R15s and R3. Err no, the official website doesn't add YZF before the R15s! I’m a middle class guy so R3 was a no-go and even if I had the money I would have gone for duke 390, which is cheaper, lighter, agile and much more powerful and a thorough Hooligan by heart .
R15s though, caught my fancy. I reasoned that it looks sexier than ever, with a powertronics ecu and 165cc rebore by joel it can smoke any sub 250cc motorcycle in India. I was ecstatic by that thought, really. On a quick glance the r15s looked like a R15 v1 with v2 “upgrades” but a slightly detuned engine which was all the more reason to get a piggyback ecu ASAP! What perplexed me that there were no head to head comparisons between v2 and S, even the reviews on YouTube were by amateur wannabes. One theme was consistent though in those amateur reviews that it vibrates and the panel fitting leaves a lot to be desired. I was like WHAT? Vibration from an r15 engine!
the new r15s looks so hot even the v2 seems pale in comparison
I took the matters in my own hand then and went on the crusade to find the truth, the first stop was Yamaha’s Showroom in Gorakhpur. A smoking hot Red R15s was on the display, I kept staring at her and there was a smile plastered on my face. Time for the test drive and first thing I noticed is the exhaust sounded meatier. A good thing I concurred. It was really very sluggish off the line though, I reasoned that maybe the weight I’ve put on my 6’2 frame and the added weight of pillion (salesman) is the real culprit here. So I thought of taking it easy for a while, let the engine warm up but then I noticed the heavy steering input it required to change directions, it was really rigid. I reasoned then, well it would hold the line better now. She just likes to be “thrown” into corners. Yes, this is the author in the following pictures of the same day. lack of any action footage is regreattble though.
the new r15s looks so hot even the v2 seems pale in comparisonthe new r15s looks so hot even the v2 seems pale in comparison
Let’s test that theory then and I gunned it full throttle in 3rd gear. My heart sunk when the revs crawled slowly and there was a large flat spot at 4-6k, no power whatsoever and it took forever to make it nudge past 7k. I was furious and sad at the same time, what is this sorcery. I mean even a budget 150cc motor from Honda or Suzuki pulls cleaner than this. I didn’t lose hope though, I downshifted and gunned again and yes, in second gear the revs did climbed normally (as a budget 150cc mil) but past 8k the engine was a screaming block of agony. Awful noises and no tractability and by extension no power either.

The sales guy started getting paranoid and said “do it slowly, why you’re giving complete throttle. Please return to the Showroom”. I complied, braked hard from 70kmph and the front dived like crazy! Wow. That’s something new, I mean honestly the nose was almost touching the front mudguards. Then I reckon this must be due to my enormous upper body, I’m not meant for R15 now. I still had to check the maneuverability and line stability so on the way back I kept it on boil and did some fast traffic filtering. Immensely stable once in a line, but heavy handed nonetheless. Another thing you would notice that in flesh it gives a proper big bike feel, it’s larger than R15 v2, feels heavier too. Main disappointment was the engine though.
that's my dad test riding
My dad judged my disappointment and we discussed the shortcomings, he’s an avid biker as well. After he took a test drive we decided there must be some problem with this specific unit. So we went on to test another R15s in Sant Kabir nagar’s Yamaha Showroom. Good thing, it was located out of the urban chaos. I could finally put it to paces on the sparsely populated one way “city-highways”. They were very friendly people and on my suggestion that maybe a bike with some miles on would be a better benchmark they provided me with not one but two R15 v2, both a year old with few crashes in the repertoire. Basically they were damaged goods. They also called in one owner of R15s who lived nearby. So I had two r15 V2’s and one R15s at my disposal.

I went on the r15s first, it was in mint condition track white color only 1200 kms done. The owner was a jolly fellow who haven’t ever rode it past 100 km/h and was proud about that fact. It felt relatively easier to get off line, felt more responsive on turning and the engine revved fine, relative to what I experienced earlier that day and not to what R15 v1 was. So I reckoned that oh without a pillion and after two services this engine settles quite nicely. Time to really push it, so I gunned it full throttle, got slightly tucked in. Up top it wasn’t any better though. Same harshness and screaming noises past 8k, typical of a two-valve air cooled budget engine. Also it hit a wall on 100km/h, in the 5th gear with the throttle pinned all the way down, the engine was pulling really slowly after 90 km/h and almost no pull whatsoever after the Ton.
author on the other track white R15sauthor on the track white R15s
pathetic camera work i know, but at that moment i wasn't aware that such a story is panning out. I was there just to have a test drive before buying the R15s.

There goes my plans to cruise on highways at 120kmph. With heavy heart I returned and hopped on the R15 v2. The brake lever was contorted on this one, but a rider make do with anything. Guys, seriously if you want to compare two motorcycles; ride them in quick succession a lot of times. No review can tell you what you can experience for yourself when riding two bikes back to back. Well, the V2 pulled much more enthusiastically from stop. Even in the first gear the revs climbed slowly but surely all the way to 10k without throwing any hissy fits or making screaming noises. Then it hit me, this is it. This is what R15 bloodline feels like. R15S needs deeper digging, it’s something else entirely.
me on the 2015 R15 V2 cyan edition 2015 Streaking Cyan Special Edition R15 v2
V2 also felt much more agile and spirited. Even the exhaust note was different; more subdued and underplaying the true abilities of the engine. In the 4th gear I was doing 100+ easily, though it pulled less eagerly after that which is understandable under the light of my 105 Kgs of bulk, pun intended. One thing that seriously pinches any experienced rider is that Chassis on the R15 V2 can hold a much more powerful engine. On the way back I swerved in and out of the traffic, V2 is quite a hoot to thrash around. My traffic filtering skills are off the chart guys. I’m getting an action camera soon to showcase that.

Just to be sure I hopped on the R15S one more time and planned on really keeping it on boil from the word go this time. Same results though, the engine was sluggish vis-à-vis V2 and it was crying out loud. I was merciless though, I kept it past 8k in every gear but first and it performed slightly better, nothing compared to the V2 by the way. Another thing is noticed is that once past 80-90 km/h the steering sorts of locks out, I literally had to counter-steer and throw it in to make any change in directions. It was like I’m on rails, hell not even trucks feel THAT stable on straight lines. My dad and I hardly agree on something but in this case he concurred i.e R15s and R15 V2 feel drastically different.
looks so pretty
So I slowed down and did some quick filtering in 2-3rd gear while gunning it all the time, after reaching the showroom, the engine was emanating the characteristic smell of overheated engines, prominently experienced in older iron-block Royal Enfield’s or any low quality engine after some “abuse” (read putting it to paces). There goes my plans to gun it all day, every day. Just to confirm once more that what I’m thinking is really true I hopped on the other R15 V2 which was in even worse condition but the engine response was typical R15. You can kill an R15 but you can’t kill that gem of an engine.
the official press release provided by the owner of Yamaha's showroom
When I explained the differences to the owner, he showed me this “official Yamaha press release” pamphlet. All the differences are there, see. He said. I was fairly convinced that only 0.4 bhp less power and 0.4 nm lesser torque won’t make such a dramatic difference. So we went on the official Yamaha motor India website and found out some glaring differences in the spec sheets, to be more precise some cleverly left out details. Also the official website says Torque is same at 15 nm @ 7500 rpm, only power is reduced but this "official dealer's page?" says otherwise. Benefit of doubt? Plausible deniability? To start with, there is no mention of four valves in the official spec sheet webpage which is consistent with how earlier I felt it struggling to rev like a typical two valve setup. On the R15 V2 page though, the four-valve is proudly mentioned.
screenshot of spec page from of R15sscreenshot of spec page from of YZF R15 v2
On the features page of r15 V2 there is a whole paragraph explaining the superiority of Daisil Cylinders but on the R15S feature page, there is no mention of Daisil cylinder at all. Which is consistent with the iron block overheat smell I talked about. Also there in nowhere mentioned on the official website that these two sport the same engine, and the R15s is just slightly detuned. Plausible deniability done right! Then I thought, that’s downright evil. That’s what villains in the movies do. Playing with people’s sentiments, Yamaha India is just a corporate giant, whatever it does is to make more money. Why purposely remove valves and strip their legendary cylinders block of the aluminum-silicon alloy goodness, that’s counterproductive, right?
screenshot of feature page from of R15sscreenshot of feature page from of R15 V2
No mention of Diasil cylinders, even the YZF moniker isn't there. That’s like disrupting the engine assembly line for shits and giggles. *evil laugh in the background*. This scenario becomes immensely economical if we entertain the notion that the engine block in R15s is entirely different. That it is a completely different 149cc block, maybe this is the one found in Yamaha’s Fz series bikes. These new Fz-s and fazers have fuel injection as well so they slid in pretty conveniently with a liquid cooling strapped on.
screenshot of spec page from of FZ-s
Another fact that solidifies my argument is that both R15 V1 and R15 V2 had 149.8 cc cylinders. Which is quite easy to confirm with simple volume equation for a cylinder if Bore X Stroke is given. The Bore X Stroke which are basically diameter and length of cylinders when put in the formula V = pie x R^2 x H gives the cubic capacity of the engine. Well, the bore x stroke of the Diasil cylinder 4 valve engine of R15 v1 and R15 v2 is 57 x 58.7 so doing the math – 22/7 x (57/2)^2 x 58.7 = 149848 cm^3 i.e 149.85 cc!

For the Fzs/Fazer engine, Yamaha’s official website provides the bore x stroke figure as 57.3 x 57.9 | Again doing the math 22/7 x (57.3/2)^2 x 57.9 = 149.3 cc and it’s standard practice to round up such displacement into lower integers hence a 149cc block. Yes, the spec sheet of Yamaha R15s nowhere mentions the bore x stroke values or how many valves are there and only that the engine is a 149cc, liquid cooled, sohc unit. Hell even the budget commuter from Yamaha i.e 125cc Saluto has clearly stated two-valve and bore x stroke figures mentioned in the spec sheet.
screenshot of spec page from of saluto
All of these screenshots are from the i.e official Yamaha Website, as shown clearly in the pictures.
Is there any doubt left still that all the pivotal information is cleverly left out? Yamaha never said it’s the same engine, they simply omitted the data which can confirm it’s NOT the same engine. Makes you think and ask the same questions I asked, doesn’t it? It’s just my opinion though, and combined with the riding experience I shared here, I’m pretty certain my hypothesis isn’t flawed. It would be nice if Yamaha can shed some light upon this issue. Even i need answers, why it felt so sluggish when slow and so rigid when going fast? Do share this story to prospective R15S buyers so they can test drive and know for themselves what they’re getting into.
Leave comments, share it, and tell us what your experience with R15S or R15 V2 is. And if you guys are curious what about my search for a new bike, well that's a topic for another article. I finally got a 200 cc machine, any guesses?

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