The Suzuki GSX-R400 got a new frame (GK73A) and new overall appearance in 1988. The new model was presented in February 1988. The redesigned Suzuki GSX-R400 got once again new fairing and shorter wheelbase, but the weight increased a bit due to the stronger new chassis and exhaust system. The model also got slingshot carburetors, polished chrome silencers, curved radiator, Tokico 4-cylinder front brake calipers and a rear hugger mudguard.
The new 4 into 2 exhaust was meant to increase the torque on the mid-range band, but had only a marginal effect.
The 400cc series were increasing popularity in Japan and a production racer with different suspension and gearing, Suzuki GSX-R 400 SP (Sports Production) was presented for 1988. It looked almost identical with the standard Suzuki GSX-R400 but didn’t have passenger foot pegs and you could spot the rear suspension gas reservoir peeking out from under the seat. Also the front suspension was different from the standard model. The SP version also had a Sports Production logo on the tailpiece.
To compete in production racing, the manufacturers produce SP (Sports Production) versions of their sports bikes. These usually have fully adjustable suspension, close ratio gearboxes and a single seat but didn’t have more power, due to Japanese motorcycle manufacturer’s power restriction code.
The SP’s are claimed to be even harder work on the road than a standard Suzuki GSX-R 400. Not that surprising knowing that it was designed for racing only.
Suzuki GSX-R400 1988 Specifications
SP model Blue/White
Dimensions and dry mass
Type (frame code): GK73A
Overall length: 1,995 mm (78.5 in.)
Overall width: 695 mm (27.4 in.)
Overall height: 1,110 mm (43.7 in.)
Wheelbase: 1,375 mm (54.1 in.)
Ground Clearance: 125 mm (4.92 in.)
Seat height: 735 mm (28.9 in.)
Dry mass (weight): 160 kg (352 lbs)
Engine type: Liquid-cooled DOHC inline-4, 16 valves
Bore x stroke: 56,0 mm x 40,4 mm (2.205 x 1.591 in.)
Piston displacement: 398 cc
Compression ratio: 11,8 :1
Maximum power: 59 hp/ 12,000 rpm
Maximum torque: 38 Nm (3,9 kg-m)/ 10,500 rpm
Top speed: about 200 km/h (124 mph)
Starting system: Electric starter
Lubrication system: Wet sump
Carburetor: Mikuni 27mm x 2