In the early ’00s, Kawasaki decided that a good way to stay competitive in the 600cc sportbike market was to just bump up displacement of their ZX-6R to 636cc. This was fine with street riders, but a bit of an issue for racers who competed in classes that were limited to 599cc. So Kawasaki also offered a limited-production ZX-6RR – the smaller engine size came with a loss of 2 horsepower (down to 123) but the RR gained a slipper clutch (apparently the first on a production 600), adjustable swingarm pivot, a super hard carbon coating to the inner fork tubes to minimize friction, and some cosmetic changes.
So despite the smaller displacement, the double R was a better bike for a certain type of rider. If one R is good, two must be better! For more on the double RR and why it may or may not have have been worth the extra $400 of MSRP, check out this review that originally appeared in the August 2003 issue of Sport Rider.
This example is further upgraded with an Ohlins steering damper and a Penske rear shock. It has 6,422 miles and looks just about new, according to the seller. Find this ZX-6RR for sale in Portland, Oregon for $5,495 here at Automania.