27 technologies that made the CBR250R possible

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The Honda CBR250R isn’t just a bunch of existing parts cobbled together to create an affordable package, it’s an all-new motorcycle specifically designed to combine low-cost Thai manufacture with a product that fits into Western ideas of quality and performance. All that and it has to meet global emissions standards that, in 2011, are tougher than ever. Here’s a look inside the technical solutions that made the CBR250R possible.

Noticing a bit of a CBR250R love affair on HFL this week? Well, in our opinion, it’s the most significant product to enter the American market in 2011. That’s right, not another liter bike or adventure tourer, but a humble little four-stroke, $3,999 250 that looks more than a little like Shamu. Why? In the last two years, the American motorcycle market has fundamentally changed. Boomers, who were the lifeblood of the industry, have begun to age out of riding a decade earlier than predicted as their ability to purchase bikes they couldn’t afford (like Shamu) dried up along with free credit. That’s left the industry up the proverbial creek without a paddle. An entire industry geared towards selling high-end products to existing customers suddenly found itself without those customers. The CBR250R? Thats the paddle.

Last week we reported that JD power had identified that the average age of a motorcycle buyer in the US had increased to 49 years old and concluded that reaching younger customers was the key challenge now facing motorcycle makers. This Honda represents the first of what we hope is a sustained effort to actually reach those new,  young customers. If this bike is successful — and it should be, the Kawasaki Ninja 250 was the fifth best selling bike in the US in 2009 — then it will prompt other manufacturers to, in the short term, import similar bikes like the Yamaha YZF-R15 and, in the long term, even design small capacity bikes with American youth market tastes in mind. That’s right, this CBR250R could lead to Honda eventually selling a small or mid-capacity UJM, cafe racer or similar in the US market.

The main criticism leveled a the CBR250R is that it makes less power than the long-established Kawasaki Ninja 250. The Honda only makes 26bhp to the Ninja’s 31. But, look at these dyno charts (via ThaiVisa) of the two bikes and you can see that the CBR enjoys a fuller mid-range, which should make its limited performance easier to exploit, especially for new riders.

According to this dyno run, the CBR250R peaks at 21.15hp and what we’re assuming is 14.49lb/ft to the Ninja 250’s 25.67hp and 12.7lb/ft. As with all dyno measurements, those figures are at the back wheel.

So, onto the technology. These two PDFs will walk you through the basics.

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Brakes/Optional ABS


Powerful braking capabilities come via a front brake consisting of a twin-piston floating caliper clamping down on a large, 296mm floating disc and a rear brake consisting of a big 220mm disc and a single-piston caliper. As an option, the CBR250R can be had with Combined ABS, which combines a front/rear-wheel interlocking brake system with an anti-lock brake system (ABS). This Combined ABS is a Honda-original brake system in which the front/rear-wheel connection generates a braking force distributed between both wheels when the brake pedal is actuated. However, for a more sporting response, when the front brake lever is applied, the front brake alone functions independently without actuating the rear brake.

The CBR250R with Combined ABS features a three-piston caliper in front, front/rear wheel speed sensors that detect the condition of the vehicle, and an ABS modulator with a built-in Electronic Control Unit. The ECU processes information from the wheel speed sensors and controls the flow of hydraulic pressure to the caliper. This advanced braking performance was achieved with an eye toward optimal handling by placing heavier items, such as the ABS modulator, near the bike’s center of gravity.

Chassis/Suspension


With the CBR250R chassis, Honda’s engineers targeted agile handling, solid tracking and sporty, responsive steering traits as key objectives. Toward that end, the newly developed lightweight and compact engine, a short 53.9-inch wheelbase, an optimized front/rear weight distribution, and a focus on mass centralization all helped shape the CBR250R into a handling star. At the same time, weight reduction and reduced vehicle vibration were achieved by optimizing the position of the engine mounting points and the frame rigidity/flex balance.

The CBR250R engine bolts up to a diamond-configuration truss-braced twin-spar tubular steel frame that is lightweight while also offering plenty of frame rigidity for optimal handling. The 37mm front fork offers a generous 4.65 inches of travel, and the Pro-Link® single-shock rear suspension uses a linkage system to provide rising-rate travel characteristics for a soft, comfortable ride during the initial portions of travel, with the damping forces increasing progressively as wheel travel is extended. In addition, the shock offers five-position spring preload adjustability. Together, these components combine to provide impressively agile handling along with rider comfort.

“Spiny” Cylinder


To reduce the flow of blow-by gasses and minimize oil consumption, a spiny sleeve design was adopted for the cylinder sleeve. With this configuration, small spines have been added to the outer surface of the cylinder sleeve to improve cooling performance and help reduce distortion of the cylinder’s inner shape. In addition, centrifugal casting allows a thin, uniform wall thickness, which aids weight reduction.

DOHC/roller rocker arm valve train


To fulfill such sport performance requirements with an eye toward efficient operation, a dual overhead camshaft layout was selected as the valve actuation system. DOHC designs improve combustion efficiency by reducing the weight of the reciprocating portion of the valves. This design also allowed Honda’s engineers great freedom in choosing the included valve angle, the port shape, and the shape of the combustion chamber—all key elements for optimal performance. In addition, the choice of a DOHC configuration contributed to improved product appeal as a sports bike as well as adding sheer performance.

In the CBR250R’s valve train, a roller rocker arm was adopted in combination with the DOHC engine configuration—a world’s-first application that has been patented. This unique combination produces a low-friction valve train with a smaller cylinder head and an ultra-compact layout for the roller rocker arm. The choice of a shim design for valve tappet adjustment reduced the rocker arm weight, while internal engine friction was further reduced by setting the valve spring load to a low level. For ease of maintenance and reduced operating costs, the valve shims can be replaced for valve adjustment maintenance without removing the camshafts. This design also allowed the engineers the freedom to incorporate a pent-roof combustion chamber with a narrow included valve angle for enhanced combustion characteristics.

The gallery below demonstrates other CBR250R technical features too.

  • http://rohorn.blogspot.com rohorn

    Sounds like marketing is paid more than engineering – Honda has a great reputation for techno-placebos, but I’ve never read so many in one spot before.

    “The aperature provided in the cowl’s layered area improves the agility for lean-in when initially turning the vehicle body”.
    What’s both sad and funny is that someone will actually believe that.

    I would dearly love to see a zippy little 250 – but if all this “technology” were applied to the CBR1000rr, we would have an 84 hp liter bike. Wow.

    Sorry, but Big Red is sounding more like Big Brown.

    • http://hellforleathermagazine.com Wes Siler

      Yeah, you kind of have to ignore presumably lost-in-translation stuff like that. I’m assuming that’s intended to say the fairing leaves room for decent steering lock?

      • http://rohorn.blogspot.com rohorn

        Good point and good advice. I like their hardware better when I tune out their PR machine.

        What would seriously intrigue me is if this engine is a good enough base for tuning. If it has the potential to make an accessable and bulletproof 35hp, they won’t be able to make enough of them.

      • Archer

        No, they really mean that from an aerodynamic standpoint- they said something nearly identical about the fairing layout of the CBR600RR when the current gen was introduced in 07.

  • Myles

    Maybe I’m just an idiot who’s obsessed with numbers – but the cbr250rr made around 40hp like 25 years ago. I mean, damn, I really don’t care about “technology” if it doesn’t lead to more power.

    HFL guys who have had seat time with both – what gives a more fun ride – CBR250 or WR250? The WR is 50% more expensive (and more than a sv650!) but they are the same engine config.

    • http://hellforleathermagazine.com Wes Siler

      Those old four-cylinder 250s were very high-spec and cost as much as a 600. They were developed for the needs of the Japanese market which has some bizarre license tiers that create demand for high-cost, low-capacity bikes. The American market wouldn’t buy a 40bhp CBR250RR for $10k+.

    • seanslides

      WR250 hands down. Granted, I haven’t ridden the CBR, but I commuted on a ninjette for just under a year, and it pretty much sucked everywhere. No power, terrible suspension, parts fell off at least once a month, and I blew the motor up just before 13,000 miles. Then again, I was spinning it at 12-13k for at least a half hour at a time, throttle turned to the stop for most of those miles…

      A friend of mine has a WR250X, and I’ve had the pleasure of beating on it a few times. The suspension works ok, the brakes are pretty good, the tire selection is great, and it’s a ton of fun. It’ll do 85 on the freeway, and if you de-smog it, and add a pipe and power commander you’ll be able to do second gear power wheelies.

      It’s really the difference between a small, slow supermoto with a funny aluminum frame, and a bike that’s trying real hard to be like a big ninja, but on a shoestring budget.

      There’s a reason the WR250 is so much more expensive ;)

  • Ian

    That looks like a pretty hi-tech valvetrain. I bet the aftermarket will start in after a year or two with cams, valve springs, and a computer. If the bottom end can handle it, there might be another 10hp hiding in the little beast. A lot of it from revs alone.

    I think it’s great news that the Ninja has competition. Kawi didn’t have to work hard on their update for 2008, and it shows. The new bike had less power, no FI, and by the accounts of experienced riders who owned the 88-07 Ninja, it was a disappointment in all areas except the plastic. Now green is gonna have to up their game.

    And because this bike will spur competition, just maybe in a couple years we’ll start seeing what I really, really want: 50hp 400cc twin or triple in a 350lb package.

    Europe, are you listening?

    • miles_prower

      Not to always sound like a KTM fanboy (but I guess I am one, having owned three), but if you’re looking for good power/weight ratio at 350 lbs wet, have you thought about a KTM 690 SMC? Wet weight is just about 340 lbs, and it puts out 63 HP at the rear wheel. It’s not a twin or triple, but the current 354 cc LC4 engine is the smoothest single I’ve ever ridden. I’ve got a KTM 690 Duke with the same LC4. Wet weight is about 360 lbs. And it’s all-day comfortable, with so little vibration that you’d guess it’s a twin.

      I previously owned a 625 SMC with a previous-generation LC4. That sucker vibrated so much that I could ride it for at most two hours before it beat the crap out of me! With lots of derestricting/tuning help from ktmforums.com plus some aftermarket parts, my guess is that I was getting 70&nbsp:HP and significantly more torque out of that engine. The front wheel lofted way too easily in 1st and 2nd gear. After all the wrenching I put into it, it was actually too much motorcycle for me, so I sold it! The Duke 690 is tame (and much smoother) in comparison.

      Or how about the Aprilia SXV V-twins with 450 and 550 cc twins? The 550 weighs just over 300 lbs wet with 61 hp at the rear wheel. Unfortunately, these suckers are race bikes that happen to be 50-state street legal, and maintenance intervals are specified in hours, not thousands of miles.

      • Trev

        What is the service interval on that SMC for the valves and other junk?

        If I remember correctly, KTM’s are usually a pain to maintain and a bit more on the expensive side for parts. I do agree that they look and perform great though.

      • seanslides

        +1 on the 690.

        Steer clear of the SXV unless you’re the kinda guy that doesn’t mind swapping pistons about as often as knee pucks.

      • Cajun58

        How does a KTM that retails for over 10 large compare to a $4K Honda?

  • seanslides

    That spiked sleeve is actually pretty damn neat. We played around with finned sleeves at the shop I used to work for in search of more surface area for better heat transfer. It looks like honda has finally found a way to cheaply produce extra surface area. In my opinion, this is WAY cooler than the lame DCT they’ve got for shamu.

    • Ducky

      I liked the roller rocker arm arrangement in the cylinder head. Plus, maintenance intervals are huge and you don’t have to remove cams to adjust the valve shims!

  • Ducky

    What this bike needs (beyond an aftermarket pipe… strictly for looks just because the stocker looks terribad), is a pair of high profile cams.

    That midrange is fat… really fat, I can imagine easily giving up a bit of that in order to help the engine breathe better in the top end (and ultimately make more power). The two bikes are fairly similar up to 9.5k RPM. But whereas the Ninja’s torque band continues with revs up to redline, the CBR’s falls… and with such a strong cylinder head design in the CBR I don’t see why another 1K rpm increase and better cams won’t make as much, if not more power than the Ninja.

  • Tim

    I want one really bad.

  • Daniel

    I got a CM450c twin from ’82. It rocks but I got to have one of these. An ABS version is pegged for me but I probably won’t get it till June. I’m expecting it to be faster than my 450 being 80 lbs or so lighter.