The Suzuki GSX-R 400 got a new frame (GK73A) and new overall appearance in 1988. The new model was presented in February 1988. The redesigned Suzuki GSX-R 400 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-R 400 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
Clutch type: Wet multi-plate
Transmission type: 6 speeds, chain drive
Gearshift pattern: 1-down, 5-up
Primary reduction ratio: 2.212
1st gear ratio: 3.166
2nd gear ratio: 2.125
3rd gear ratio: 1.631
4th gear ratio: 1.333
5th gear ratio: 1.173
6th gear ratio: 1.083
Final drive: 3.066 chain
Frame type: Aluminum angular pipe double cradle
Trail: 101 mm (4.0 in.)
Front suspension: Telescopic, coil spring, oil dampened with anti-dive
Rear suspension: Full floater suspension system, spring pre-load fully adjustable, oil dampened
Front brake: Dual hydraulic disc, four piston calipers
Rear brake: Single hydraulic disc, dual piston calipers
Front tire dimensions: 110/70-R17 53H
Rear tire dimensions: 140/60-R18 64H
Ignition type: fully transistorized
Ignition timing: 15º BTDC below at 1650 r/min and 35º BTDC above 3.500 r/min
Spark plug: ND U24FS-U or NGK C8HA
Battery: 12V 39.6 kC (11Ah)/10HR
Generator: Three-phase A.C. Generator
Headlight: 12V 35/35w x 2
Power/weight ratio: 2,57 kg/ps
Center stand: Yes
Fuel tank: 18 l.
Reserve: 3.5 l.
Engine oil: 2.6 l.
Front fork oil (each leg): 397 ml.
Cooling solution: 2,185 ml.
Image Gallery Suzuki GSX-R 400 1988