A totally new model. The air cooled, four valve GS400E engine traces its roots back to the first Suzuki four-strokes. The GS400E was a very short-lived model and was soon replaced by the GS500E.
GS 400 E 1991
Overall Length: 2 085 mm (82.1 in)
Overall Width: 750 mm (29.5 in)
Overall Height: 1 050 mm (41.3 in)
Wheelbase: 1 405 mm (55.3 in)
Weight: 169 kg (373 lbs)
Engine type: Air-cooled 399 cc inline-2, DOHC, 4 valves.
39 hp/ 9.500 rpm, 3,2 kg-m/ 3.000 rpm.
This seems like a very interesting bike... its a 400 CC 4 valve version of a GS500E of the same year... I would be interested to find something like this and bump it up to a GS500F spec... maybe take the cylinders and head and bore them to fit the GS500 case... then throw the GS500F carbs back on for better fuel regs and pray everything holds together nicely... then you could truly call it a GSX500F :) I would guess it would be a considerable jump in efficiency and performance though the GS400 cams might need to re ground for the air flow needs of the larger displacement.
Hate to burst your bubble, but it's the same bike except 100cc's less. The 400E and the GS500E both have 4 valves TOTAL.
ahh damn, im retarded some days... its the older ones with the 8 valve engines...