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ZX750J / K - 1991
The ZX 750 J / K was a new development with aluminum frame without beams, upside-down forks and a short-stroke engine with rocker arms instead of bucket tappets. The K-model was the single-seater racing version, which allegedly only 1000 times was built around the world, but in fact about 2500 pieces were produced. It differs from the basic model J by increased engine power, which has been achieved by more aggressive timings, altered camshafts and dual valve springs, a revised gearing with an extremely long first gear, flat slide carburetor and a fully adjustable suspension. To reduce weight, an aluminum tank was installed, also found on the rear frame using a relieved. This came a list price of 25,000 DM at that time. The J one might regard as most widespread ZXR today, however, because it was more affordable.
Specifications: Displacement: 749 cm³ Bore x stroke: 71 x 47.3 mm Power: J 74 kW (101 hp) / K 90 kW (122 hp) Weight: J 225kg / K 220kg Fork Stanchion diameter: J 43mm / K 41mm Tyres: 120/70/17 front, rear 180/55/17 ignition: from 10 ° before TDC (at 1100 / min) to 42.5 ° BTDC (at 6200 / min) timing J: inlet opens 25 ° BTDC closes : 55 ° after UT Duration: 260 ° Exhaust opens: closes 55 ° before BDC: 25 ° ATDC Duration: 260 ° timing K: opens inlet: 39 ° closes BTDC 69 ° ABDC Duration: opens 288 ° outlet: 65 ° before BDC includes: 35 ° ATDC Duration: 280 ° Power Kitmotor 1992 140hp at 13,000 / mi