Kawasaki Ninja 250R: $1500 Streetbike Surgery

Ninja Turtle No More!

Kawasaki’s Ninja 250R narrowly missed out on the win in this month’s 250cc sportbike shootout, which may come as a rude surprise to its many devotees. But with its off-idle roughness, paltry low-rev power and overly erect ergonomics, the “Ninjette” has some issues to address if it wants to regain its status as King of the Quarter-Liters. The littlest Ninja has been around for nearly three decades, and in that time numerous solutions to its shortcomings have been suggested by resourceful owners and the aftermarket. What could the bike become if we tapped into that vast storehouse of knowledge? We scoured the Web, determined the most sought-after upgrades and gave ourselves a $1500 budget to find out.

First order of business was dealing with the Ninja's fussy off-idle engine behavior, Complaint #1 amongst owners of all skill levels. The problem is easily solved by adjusting the twin carburetors' pilot air screws, a procedure that's thoroughly documented on the Ninja 250 Riders Club forum (_www.ninja250.org_). Even better, it's free!

While we had the carbs off, we decided to install Dynojet’s Stage II jet kit (part number 2139) in anticipation of an air filter and exhaust upgrade. The kit comes with several sets of larger main jets and replacement needles, as well as comprehensive installation and tuning instructions. Not sure what carburetor mods are best for your bike? The aforementioned forum’s wiki feature is an invaluable resource for curious owners and inexperienced DIYers.

With the fueling taken care of, it was time to add more air to optimize engine performance. With the bodywork removed to access the carbs, swapping the restrictive stock foam air filter for a high-flow cotton K&N unit was accomplished in under 5 minutes. One great thing about the Ninja is its simplicity, which makes it convenient for owners and aftermarket manufacturers to work on. Thus performance parts are surprisingly affordable and easy to install. A full Jardine RT-5 exhaust system cost less than a slip-on for a ZX-6R, and only took 30 minutes to bolt on. The carbon-canister system shaves off more than 9 lbs. compared to the ungainly stocker, and is perfectly sized to match the bike’s diminutive stature.

Strapped to our in-house SuperFlow dyno, the Ninja’s engine upgrades proved well worth the minimal investment in time and money. While peak output only rose by 1.7 horsepower (27.1 bhp @ 10,700 rpm vs. 25.4 bhp @ 11,100 rpm), power builds faster and is sustained longer. The modified bike reaches the stocker’s peak torque output 2900 rpm sooner, and there’s at least a 1-bhp gain from 6000 rpm on up, with a maximum difference of 4.2 bhp near redline where the stocker’s power falls off dramatically. That may not sound like much, but it’s a 20 percent improvement!

Out in the real world, the effects of the engine upgrades on rideability were impressive. The bike proved eager to start, required a fraction of the time to warm up and revved up off idle crisply. The power step at 6000 rpm was backfilled, and the midrange felt significantly fatter. With the throaty snarl from its Jardine exhaust and its extra top-end oomph, our modded Ninja begs to be caned. It’s a changed machine!

As with any budget bike, the Ninjette’s suspension lacks sophistication. Owners are eager to find cost-effective ways to improve their bikes’ suspenders, and for many that means swapping out the fork springs and shock for firmer Ninja 500/EX500 components. The shock on the second-generation Ninja 250 (2008 and later) is stiffer than on earlier models, but the fork still runs the same super-soft springs, and the resultant chassis imbalance can be problematic when charging through turns. We slid in Race Tech 0.80-kg/mm fork springs selected to suit our test rider’s 175-lb. weight, and replaced the fork oil with RT’s 15-weight Ultra Slick Fork Fluid to increase damping. The result is much better front-end feel and a big reduction in brake-induced fork dive. Speaking of brakes, with our bike’s increased power and firmer fork, the brakes became the weakest link. Swapping the stock rubber hoses for stainless-steel lines from Galfer was all it took to bring them up to par, and made front-brake actuation a two-finger affair.

Although the Ninja’s upright riding position is comfortable for low-speed commuting around town, it feels awkward when the pace picks up on a twisty road. Replacing the stock bolt-on handlebars with Woodcraft clip-ons dropped handlebar height a half-inch, making for a more aggressive riding position. An added benefit is, with the top-mounted stock bars out of the way, you can experiment with fork height. We raised the forks in the triple clamps and liked the way it quickened the steering.

Other annoyances were a lack of wind protection and legroom. Fitting a taller Double Bubble windscreen from Zero Gravity resulted in a sizeable pocket of still air. And changing out the chunky, rubber-clad stock footpegs for thinner Competition Werkes aluminum pegs gave us a quarter-inch more legroom while increasing cornering clearance by the same amount, compensating for the lowered front end.

With engine performance, handling and comfort elevated, it was time to do something about the Ninja’s appearance. The ’08 aesthetic update was a big improvement, but there was still work to be done. Universal flush-mount turnsignals from Bikemaster needed some modification to fit the fairing openings, but worked well to streamline the surface. Kawasaki’s accessory solo seat cowl was an obvious choice for “sportifying” the rear end. With the passenger seat removed there was no need for the passenger footpegs, but the right-side mounting bracket also holds the muffler. Aftermarket brackets are available, but we opted to make our own from a piece of flat bar stock. With Targa’s fender-eliminator kit installed in place of the stock 18-inch plastic appendage, the 250’s backside looks sleek and suitably sporty now.

Performance-tuned and spiffed-up, the Ninja 250R is now worthy of the family name. More power and better handling encourage experienced riders to show the big bikes who’s boss on serpentine roads, while improved fueling makes the bike even friendlier for beginners.

Some would argue that $1500 is too much money to spend on a $4000 motorcycle. They haven’t ridden our Ninja.

Ninja 250 Riders Club


Bikemaster 4900 Alliance Gateway Fwy. Fort Worth, TX 76177 877.848.1320 _www.bikemaster.com_
Turnsignals $19.95
Competition Werkes 1382 Duke Rd.Sutherlin, OR 97479 800.736.2114 _www.competitionwerkes.com_
Footpegs $54.95
Dynojet Research, Inc. 2191 Mendenhall Dr. N. Las Vegas, NV 89081 702.399.1423 _www.dynojet.com_
Jet kit $85.65
Galfer USA 310 Irving Dr. Oxnard, CA 93030 805.988.2900 _www.galferusa.com_
Front brake line $98
Rear brake line $54.50
Jardine Performance Products 1180 Railroad St. Corona, CA 92882 951.739.5900 _www.jardineproducts.com_
RT-5 exhaust system $520
Kawasaki Motors Corp., USA PO Box 25252 Santa Ana, CA 92799 949.770.0400 _www.kawasaki.com_
Passenger seat cowl $85.95
K&N; Engineering, Inc. PO Box 1329 Riverside, CA 92502 800.858.3333 _www.knfilters.com_
Air filter $59.99
Race Tech Suspension 1501 Pomona Rd. Corona, CA 92880 951.279.7171 _www.racetech.com_
Fork springs $124.99
Fork oil $29.99
Targa Accessories, Inc. 21 Journey St. Aliso Viejo, CA 92656 949.362.2505 _www.targa1.com_
Fender-eliminator kit $98
Woodcraft Technologies 105 Baldwinville Rd. Winchendon, MA 01475 978.297.2977 _www.woodcraft-cfm.com_
Clip-on handlebars $179.95
Zero Gravity Corp. 912-A Pancho Rd. Camarillo, CA 93012 800.345.9791 _www.zerogravity-racing.com_
Windscreen $80.99
Total $1492.61
Trick photography? Not exactly, though our photo model did have to drop the clutch from redline at 5 mph to get the front wheel up. Our modded Ninja is peppy, but not quite capable of power wheelies.
Targa’s undertail kit lets you ditch the stock rear fender without cutting or drilling the bodywork or frame. It even comes with mini-turnsignals and OE-style wire connectors.
Zero Gravity’s legendary Double Bubble windscreen is a few inches taller than stock, which goes a long way toward warding off windblast, as well as improving the Ninjette’s looks.
The stock rubber-covered footpegs scream commuter while these Competition Werkes aluminum pegs exude racebike style. The slash-cut design improves cornering clearance.
Trick photography? Not exactly, though our photo model did have to drop the clutch from redline at 5 mph to get the front wheel up. Our modded Ninja is peppy, but not quite capable of power wheelies.
Woodcraft’s clip-ons were designed for the Ninja 250. They mount to the fork tubes below the top triple clamp instead of above, and are as low as possible without contacting the bodywork.
Reducing weight and increasing horsepower are always desirable. Jardine’s RT-5 exhaust has the added benefit of making the 250cc twin sound like a motorcycle instead of a vacuum cleaner.
Cornering speed is the key to quickness when riding a 250. With the 0.80-kg/mm Race Tech springs and heavier 15-weight fork oil, the Ninja’s front-end feel was greatly improved.