Hi Guys :D
I have an XJ750 R , engine and frame Number, 45T-000323 and it has a rear DISC brake , complianced in Australia 1/1984 but the dealers say it should be a drum brake yet it appears standard and the pads are XJ900 pads.
Also photos of English XJ750,s show a rear disc :(
On Enduro's you can find these no.s at Yamaha online parts catalog.