Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/146698
~ RIDINGIMPRESSION 1993 Suzuki GSXR750 and 1100 ~ By Paul Carruthers and Kit Palmer Photos by Tom Riles and Carruthers f it ain't liquid-cooled, it ain't #$%*. That seems to be the general concensus for sportbike manufacturers these days, with Suzuki the latest to follow that line of thinking with the allnew GSXR750 and 1100 featuring liquid cQoling for the first time. Given the opportunity to ride both the 1100 and 750 on the race track at Road Atlanta only days prior to the WERA Gr,and National Final, we spent the majority of our track time with the 750, saving the pre-production 1100 for a street-riding impression on the back roads and freeways of southern California. While the liquid cooling is the biggest thing to change on the new Suzukis, it's not the only change. Read on: ' I Tech, tech, tech The introduction of the liquid-cooled 1992 GSXR600 put Suzuki back on the map in the dog-eat-dog world of 600cc Supersport racing. In the capable hands of Britt Turkington and Dave Sadowski, the Suzuki was competitive again. Although they didn't beat the top ,Honda CBR600s in the AMA/CCS Series, they came close, and stood on the winner's rostrum more than once. Now Suzuki is hoping for similar results from their GSXR750 - and you can bet Turkington and new Yoshimura Suzuki recruits Thomas Stevens and Donald Jacks are also banking on it. This time the competition comes not from Honda, but from Kawasaki, whose ZX7 has proved to be the dominant machine in 750cc Supersport racing with Scott Russell winning the last three class championships. Suzuki must have been pleased with the design and results of the GSXR600, because the new 750 and 1100s are near carbon-copies of their smaller sibling. Those similarities start with the powerplants. . Compact. Powerful. Water-cooled. Those seem to be the key words when you spe~k of the engines in the new Suzukis. The compactness comes primarily from a decrease in distance between ,the two cylinders, and through the placement of the starter clutch behind the cylinders. For '93, both the 750 and 1100 engines are only 420.5mm wide (compared to last year's 489mm) and are surprisingly narrower than the 400cc Suzuki Bandit (451mm). The 1100's engine is 15mm taller than the 750's, but both engine designs allow for a lower center of gravity since both crankshafts sit lower in the frame (750 - 27mm, 1100 -20mm). . The cylinder head and combustion chambers have also shrunk, thanks to the use of a direct activated valve train rather than the rocker type used on past models. No longer using rocker arms, the new system is adjusted. via a shim which is located under each valve bucket; and the adjustment interval has jumped to 7500 miles rather than the 3500-mile adjustment required on last year's models. The increased interval. is needed because the camshafts now have to be removed in order to adjust the valves. I ' In order to cut reciprocating mass, the valves now use only a single spring per valve rather than the fwo used in years past. In addition; the valves themselves now feature a 4.5mm stem. The new valve train works in conjunction with a new valve angle of 16 degrees, allowing the use of a smaller cylinder head and combustion chamber. As a resulf, the compression ratio is pumped up from 10.9:1 to 11.8:1 on the 750 and 10.0:1 to 11.2:1 on the 1100. The number one a~d four cylinders also feature straighter ports, thus improving cylinder charging efficiency. The pistons on both bikes have been lightened, some 4% on the 750 and 5.2% on the 1100. The 1100's connecting rods have also changed to lighter bolt-up types, similar to those introduced on the 750 back in 1990, which reduce the loac;l on the big end of the rod while also increasing strength. The 750's bore and