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They look like H1 model forks.
The easy visual way to tell is the fork bottoms because the mudguard mounts are different.
The L models fingers for the mudguard mounts are longer going
half way along the chrome stanchions.
The rear mount on the H model is shortish closer to the caliper mounts
ZXR250 forks are notably different again at the bottom with 3 step change in section (and longer axle to top clamp)
The H models had the same calipers as KR-1S and common ZZR models bohemouths.
The L model changed to smaller less grunty calipers
even though there were several options for the anodising colour
the H models are pale yellow gold and
the L models generally more deeper gold or bronze colour (it does fade). The L models with the black frames/bodywork have matching black fork bottoms (bronze anodising)
the H1 model had the triangulated braced swingarm. (10mm shorter than the KR-1S, 30-40mm wider at the pivot, but can be reduced)
the H2 went to the fish shaped swingarm (not a good translant)
the L also had this swingarm but with the pressed style frame rather than the extruded blocky square one of the H.
Diameters...
as scooble says (I think) and your dimensions confirm...
the H models are ~50mm ~50mm triple clamp mounts
the L models more modern 50mm top, 52mm bottoms diameters at the clamps (ready to accept trick R6 forks

)
Wheels
The ZXR400 wheels are all the same (F 3.5x17, R 4.5x17). not to be confused with narrower (earlier) ZX-4 wheels
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92170-1028 carb vent hose wire hanger/tidy clamp (from the carb parts diagram) but its not the one down by the right footrest - cant think where it lives (alternator?)
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triple clamp/fork spacing betwen front wheel (very rough info)
ZXR400 yoke 210mm Hub xx Brakes 130mm total Disk offset ACROSS HUB ModelYear (centreline plane braking surface)
GSXR1000 yoke 207mm Hub xx BRAKES 132mm Disk offset ModelYear
YZF750 yoke 210mm Hub xx Brakes 135mm Disk offset ModelYear
R-1 yoke ?? Hub ?? Brakes 127mm Disk offset ModelYear
ZX-6 yoke 210mm Hub ?? Brakes 135mm Disk offset ModelYear
CBR600RR wider than 210 at yoke? ?214mm? hence Brakes 137mm rotor plane to plane
each manufacturer has their preferred fork spacing determining or determined by the front wheel hub width and brake offset,
if you stick to one make/breed generally less hassle (shaving/spacing) involved than picking clamps, forks, wheels from three different donor makes (different axle diameters accomodated with wheel bearing swap)
... a narrower wheel hub you could space the disks outward or offset calipers inwards (not radial calipers... need to alter hub or triple clamp)
... hub too wide.. you could have the hub milled/lathed narrower by several mm without reducing rotor bolt thread depth