Nice to see more folks getting to know the '90 sport! They have excellent potential and are essentially a watered down F1, so the handling can really be superb. I modded one a few years ago that friends christened "The Cadillac" and have a write-up on the build process and riding experience at
http://loudbike.blogs.com/loud_bike/2005/02/fits.html and
http://loudbike.blogs.com/loud_bike/2005/10/ode_to_a_loudbi.html.
Check your motor mounts on the right side at the boss on the cases. If you see a 6mm spacer between the frame and the case, you can swap for a 900SS engine. Although very few made it to the US, the first run of 900SSs made by the factory used the 750 Sport frame and bodywork.
To build it (it was a cash neutral proposition after I sold the leftovers on e-Bay), I took one slightly used 1990 Ducati 750 Sport chassis, oil cooler, F1 aluminum slip-ons and bodywork - then, blended in from a doner 199X Ducati 900SS/SP:
Fully adjustable, recently rebuilt Showa forks
Polished triple clamps
Bars, master cylinders and controls
Carbon fiber clad instrument cluster
Carbon front fender
17” Front wheel with polished accents
Fully-floating, cast iron front rotors
Brembo P30/34 4-piston calipers
Polished swing arm
17 x 5.5” rear wheel with polished accents
Polished header pipe
Kokusan ignition (mounted below battery box)
900SS Motor:
5-angle valve job (new valves, seats, guides, MBP collets
New belts
Rewired ignition pickups
Yoyodyne lightweight flywheel
Yoyodyne clutch slave cylinder
Recent Barnett clutch pack
NOS Monster pistons and rings
Carbon belt and clutch covers
Carbon sprocket cover
41mm Keihin FCRs on short manifolds
Nichols cylinder head studs
..And then add
2001 900SS rear shock (13 5/8”)
Braided stainless lines
39 tooth AFAM sprocket
Gold DID x-ring chain
New 15 tooth primary sprocket
Polished rear sets and pegs
New wheel bearings
Michelin Pilot Power tires (120/17 and 180/17)
I know of at least 6 others that have been since built to a similar spec.
BTW: Guys; why are you swapping to the later oil cooler location? The fairing mounted system gets cleaner air and does an excellent job. If you want "trick", plumb it with some braide stainless lines...
Enjoy - They are wonderful bikes..