The GSX-R750 is a sport bike from Suzuki's GSX-R series of motorcycles. It was introduced in 1985 and can be considered to be the first of the modern racer-replicas with many race-derived technologies and the looks of a Suzuki Endurance racer at an affordable price.Although this model looks very similar to the previous '89 model many changes were made. The 90 model featured changes to the engine, suspension, body work, brakes and chassis. This was the first GSX-R to be fitted with inverted forks as standard (USA models retained the conventional forks until 1991), and returned to the bore and stroke dimension of the original long-stroke engine.
The engine returned to the 748cc engine bore and stroke dimensions of the original long-stroke engine but still maintained the 13,000rpm redline. It now featured mm valve (smaller then the 88-89 short stroke but larger than the 85-87) and used larger carburetors. The new Mikuni model BST38SS carburetors were 38mm diameter and featured an additional high-speed circuit (circuit was blocked in USA models) and the slide breathers were now divorced from air box. The exhaust system was also changed, gone were the dual silencers and replaced with one stainless steel silencer on the right side. The transmission output shaft was lengthened to accommodate a wider wheel. A new curved oil-cooler design and oil lines (attached to the oil pan similar to the original 85-87 engines) were installed.
The frame was changed for 90 and used some of the features from the '89 GSX-R 1100 frame. The rake was now 25.5 degrees and wheel base 55.7 inches. The front suspension now had inverted forks, the triple clamps (yokes) and handlebars were changed to accommodate the new forks. The rear suspension featured a new damper (shock) and swingarm. The rear damper (shock) now had a remote reservoir and damping adjustment. The revised swingarm now featured cast ends for the axle adjustment. The rear wheel was widened to 5.5 inches (previously 4.5inches) but the tire size remained the same. A non-adjustable steering damper was added which attached from the left frame rail to a clamp on the left fork (US models did not receive the damper but the frame had the tapped mounting holes). The rear sprocket carrier and sprocket changed to a six-bolt design (previously five). The front brake rotors changed to a slotted design (previously cross drilled holes).
The body work changed slightly also. The side vents became less rectangular and in a slightly different position. Anew fender was also used with the inverted forks (except US).