Been on to ya web site, seems ya only make bits for 91 and up, is this the case.
Mine is a 4 speed 1990 sportster..

Actually, the 91-03 style will fit on a 90, it's just that there isn't a carb bracket that's really correct that I'm aware of. As you know, the 90 breathes off the cam cover, and the two bolts for mounting the air cleaner are 5/16-18 jobs. On the 91 and later, the breather bolts are 1/2-13. So the holes in the mounting brackets are too big. If you can solve that problem, I believe you can make it work.