Kawasaki knew many owners of its popular ZX-6R Ninja series wanted more horsepower, but hands were tied by racing rules. Until, that is, the idea of building a slightly bigger, 636cc engine for the street version while leaving the racier ZX-RR in its traditional 600cc designation. The results are a revolutionary middleweight sportbike that's become a favorite of stunters and cornering junkies alike.
When first introduced in 2003, the 636 was instantly applauded for something heretofore missing among in-line, four-cylinder 600s-a midrange. Twist the throttle on your average 600 and nothing much happens until the tachometer winds its way above the 10,000 mark, but while the 636 doesn't offer the thundering, immediate shunt of a big twin-cylinder sportbike, it does have a surprisingly broad spread of power from as little as 6000 rpm.
Rack that up to a vastly different set of specs over previous models, including lighter pistons that rev higher and offer more top-end power, a redesigned cylinder head and even racier cam profiles. This makes for a sportbike that will wheelie without too much right-wrist acrobatics and the bugger even sports a slipper clutch to eliminate rear-wheel hop when banging down several gears at once. The extra cubes also help the 636 cut a quick line in any stoplight Grand Prix as its rear tire will be biting for traction while your buddy on his traditional 600 is still waiting for the wick to light.
The 636 is a fine all-around sporting package, made even better when the crew at Kawasaki blessed the middle Ninja with a stiffer new twin-spar aluminum frame for the 2005 model year painted sinister black (which resists the worst you and Ma Nature can throw at it) and with a slightly longer swingarm than before for added stability. Down the front straight of most racetracks, the 636 had a good 8 to 10 mph over its 600cc competitors in many cases, and testers raved about how this thing loved being flung into corners more than anything this side of a roller-derby princess.
The power is no joke-the 108 rear-wheel horses can help you reach the far side of 160 mph and can catch the inexperienced off-guard if they're not careful.
The 636 comes with a wonderful, buzzy roar from its airbox whenever the juice is let loose, and the quotient of spine chills can be increased with a slip-on exhaust for a few hundred bucks-which seems to be the hands-down most popular mod, according to our readers.
"I have owned my 2006 636 for about six months. When I bought the bike it was not in perfect shape (wrecked). But since this was a second bike that was going to be a dedicated track bike I figured it would be a great deal.
"After doing a lot of research on the Web I found that the 636 is a great all-around bike. Great midrange and high-end power (for a 600) and the ability to initiate turns with little effort helps.
"When it comes to the track there is very little this bike needs, since it comes stock with a lap timer and a slipper clutch. I did do the ECU "jumper" mod-this helps with the higher end of the power band. I also changed the brake pads for more stopping power to the EBC double H's. The stock pads left a little to be desired. Also, I changed the rearsets to Vortex to help with clearance in the turns.
"The only real problem with the bike is the stock tires. The Bridgestone Battlax's are like riding on PVC pipe. I switched to the Pirelli Supercorsas. I use them for track riding and street riding-great feedback and are good with heat cycles. But this is an easy fix.
"I have enjoyed this bike very much and it inspires confidence in turns and on the straights."
Miles Done: 3000 (track)
Mods: Vortex rearsets, Vortex mirror block-offs, Vortex fairing stay, E-Racing fairings, Pirelli Supercorsa tires
Best Upgrade: Pirelli Supercorsa tiresFavorite Aspect Of Bike: "Lap timer and inverted forks."
Riding Style: "Aggressive (track riding)."