1982 Kawasaki KZ1000J2.
Numbers matter, even subtle numbers. Like the difference between 1,015cc and 998cc. Arriving at the smaller number meant decreasing the bore on Kawasaki?s 1980 KZ1000G from 70mm to 69.4mm on the 1981 KZ1000J. In addition to this minor adjustment to meet racing rules, just about everything else on the motorcycle had been changed as well, with the exception of the 66mm stroke.
Let?s go back a bit, to late 1972 when Kawasaki introduced the 903cc Z-1?the Killer Kaw, later labeled the KZ900 in 1976. It had a perfectly equal bore and stroke, 66 by 66mm, which was then bored out 4mm in 1977 to make the 1,015cc KZ1000A, maintaining the KZ?s reputation as the biggest, strongest UJM on the market. But the competition was getting fierce. Move up to 1981, and the new J model was an absolute delight?a street bike with Superbike potential. When the boys at Akashi, Kawasaki?s brain center, were given the task of revamping the 1,015cc KZ, the company?s bread-and-butter bike, they did it with gusto. It may have taken them a couple of years, but it was time well spent. 1982 Kawasaki KZ1000J2.
First, as always, more power. They lightened the crankshaft by hollowing out some bits, used a pork-chop flywheel rather than the previous full-circle design, and in the end shaved 4.9 pounds off the weight. Bigger valves went in the two-valve heads, and bigger, lighter, aluminum-bodied 34mm constant-velocity Mikuni carburetors were fitted. They fiddled with the camshaft timing s...