Dinosaur Mine
Take one ancient sportbike the ZX-7R nip here, tuck there and what have you got? (A nicely spruced ancient sportbike?)
By Marc Cook
Anthony Serpa loves his ZX-7Rs. Plural. Actually, he's only had one at a time because his first Ninja, a year-2000 model, was stolen from the side of the freeway with a flat tire after he was forced to leave it and get help. His insurance company paid it off, and those of us with a great deal more sense than Mr. Serpa would have opted for something a decade or so more current. Not our little Canadian friend. He turned the payoff into an ex-demo, '01 model. And, through the labyrinthine set of connections managed by all Canadians living abroad, Serpa hooked up with our own Geek from the Great White North to have his 5000-mile pride and joy become...ta da...the latest This Old Bike.
It's a good subject bike, actually. The ZX-7R has seen a long and illustrious racing career, and as a result remains an emotional favorite of Kawasaki fans everywhere. So as we ease into the '04 model year-a year without the ZX-7R and other stalwart Kaws such as the ZR-7 and the ZX-9R-it seemed appropriate to take a whack at the Seven and see what could be done.
Never forget that this is an older design-even working on it is a real pain compared with "modern" Kawasakis, a clear indication that there is such a thing as evolution in design and manufacturing-and there's really only so much you can do. We spent most of the time working on three areas-reducing weight, increasing power and taming the suspension. Oh, and there were a few cosmetic improvements as well.
Let's start with the engine, then. Kawasaki's 748cc inline-four has been tweaked and modified by various race teams-and punched out to 800cc for AMA Superbike in '03-but has never really gotten much attention in the streetbike world. California bikes, in particular, seem to carburet poorly, so our first order of business was to install a Factory Pro jet kit (800/869-0497,
http://www.factorypro.com ). We used the K51-0.5 "drop-in" kit ($129.95), which includes new emulsion tubes, slide springs and an assortment of main jets. (Stock is 170 outboard/180 inboard; we used 168 outboard/178 inboard.) Factory Pro also sent along a BMC oiled-gauze air filter ($74.95). Unfortunately, the company was out of stock on its ignition advancer for the ZX-7R as the project came together.
While mucking about around the airbox, some three pounds of emissions junk went into the hopper, including the California-spec charcoal canister, air-injection valve and carb float-vent apparatus. Factory Pro's Marc Salvisberg recommended removing this flotsam and simply routing the carburetor vent lines into the airbox through an elbow fitting, which we duly did. "This mod dates from the old Kinko's Kawasaki racing days. I still don't know for sure why that valve is in there, only that [the bike] works fine without it."
After installation, we tweaked the setup slightly, adding one Factory-supplied shim under each needle to help cure a midrange lean spot, and turning the pilot fuel screws out from the recommended two turns to three to fix an off-idle stumble.
On the downwind side of the engine went a D&D Performance (817/834-8961,
http://www.danddexhaust.com) full exhaust system. This is the company's 4-into-2-into-1 configuration with a polished aluminum muffler (part number 802-22A, $585). We'll say this: You can't be an introvert with this pipe. On our normal noise test-6000 rpm without load, with the sound meter positioned 20 inches from the exhaust tip at a 45-degree angle-the D&D belted out 109 dBa of raucous, wailing, four-cylinder ...um...noise. Even young Serpa, whose automobiles all have rumpity pipes, thought it a tad loud. We also have a few issues with the fit of the pipe. On this ZX-7R, the flanges for the outboard cylinders did not line up perfectly with the exhaust ports because the collector pipe was too close to the frame crossover below and behind the engine. The pipe needs to twist upward at the rear but can't. The center pair fit fine, as did the Y-pipe after the collector pairs and the muffler. One installation note for you Ninja owners: You must install the head pipe for the outboard cylinders first because it's stacked on top of the inboard set below the engine; nowhere is this suggested in the instructions.
Buttoned back up, Serpa's Ninja made considerably better power. The last Zed-Seven test bike we had through here punched out 108.6 horsepower and 53.7 foot-pounds of torque. Anthony's mule, before we got our paws on it, made 106.4 hp and 53.6 foot-pounds. As configured, it put out 111.9 peak hp with slightly less peak torque. Compared to the stock bike, the modded Zed has marginally more torque between 3000 and 6000 rpm, and considerably more from 9500 rpm to the 12,500 rpm ignition cutoff. More power is always good, and it certainly helps keep the hefty Ninja on its toes.
Beyond extra thrust, This Old Bike benefits from better suspension and dramatically improved tires. Bridgestone BT012SS buns replaced the OE Dunlop D204s, with the rear going to a 180/55 from the stock 190/50; the front is a 120/70. The 'Stones are nicely rounded and compliant, plus sticky enough for any kind of halfway sane street use. The taller, narrower rear quickened steering without impacting stability. (Hell, this bike has enough inherent stability for three normal sportbikes. Call it the Queen Mary of canyon thrashers.)
The Kayaba inverted fork went to GP Suspension (
http://www.gpsuspension.com, 503/723-7793), whose owner, Dave Hodges, was until recently a partner in the Circuit-1 suspension business. He revalved the innards-including reprofiling the compression and rebound-adjuster needles to spread out the adjustment range-inserted 0.9 kg/mm springs and adapted the stock ride-height adjustment system into a more conventional spring-preload setup. The total cost was $500.
To go with the reworked fork, a Fox Twin Clicker shock ($629; 800/369-7469,
http://www.foxracingshox.com) replaced the dreadful stock Kayaba. This remote-reservoir shock comes with the obligatory rebound- and compression-damping adjustments (eight-way and 36-way, respectively) plus a threaded-collar spring-preload adjustment. This particular shock does not, however, have a length adjustment, and Fox warns that putting it on a post-'96 ZX-7R will result in reduced ride height. To compensate, we placed three washers (five-eighth-inch inner diameter, one-eighth-inch thick) between the shock clevis and the frame, which raised the ride height approximately three-quarter inches over stock.
Taken all together, the chassis mods bring the Ninja to life. It steers with alacrity-finally!-yet is still reassuringly stable. It tracks over bumps and can fully use the newfound brake performance thanks to Galfer FD156 front brake pads and steel-braided lines ($27.99 and $79.99, respectively;
http://www.galferusa.com, 805/653-5012). No, the Ninja doesn't magically become a GSX-R750 in terms of agility, but these mods close the gap reasonably well.
You can't have a green Ninja and resist the bling-bling, so Targa Accessories (
http://www.targa-acc.com, 800/521-7945) coughed up a color-matched solo seat cowl ($189.95), undertail ($264.95) and hugger ($249.95). It all went together quickly and easily-the pieces are suitably robust and beautifully finished-though there was a slight mismatch between the seat cowl and the bike's graphics. Bling is good.
How'd we do on weight? According to calculations, the Ninja dropped 13 pounds, with the lion's share coming from the exhaust system (7.7 pounds saved), removal of the emissions junk (3 pounds) and the 520 chain conversion using aluminum sprockets (2.4 pounds). The rest came in dribs and drabs, with the Targa seat cowl being marginally lighter than the seat it replaced, and the Fox shock carrying less flab than the stocker.
In the end, Serpa is delighted. His Zed looks and feels a lot newer, which gives him some rational footing for being so in love with this Jurassic-period sportbike. Like infatuation knows anything about logic, eh?
by Strika » Thu Mar 09, 2006 7:37 pm bite me biatch !!!!
andi - Red GPZ900R, GPZ750R1, KLR650 Tengai, KLR250
