try ebay if im not mistaken i think a 90-93 are the same BUT im not 100% sure so check it out but i did find this
eBay Motors: KAWASAKI KX125 1991 LOWER HALF ENGINE NICE LOOK!! (item 170167107358 end time Nov-14-07 15:28:11 PST)
eBay Motors: KAWASAKI KX125 1991 LOWER HALF ENGINE NICE LOOK!! (item 170167107358 end time Nov-14-07 15:28:11 PST)