you can plug the tail light off of a tractor if you wanted to... or a honda civic... or a flashlight... or the red blinking light off of an F16.... it really doesn't matter what you plug into it as long as it has two or 3 wires.... a +. a + and a - ... and if it doesn't, you gotta know how to get around it... and you gotta be smart enough to figure out that the black wire may actually be green on your harness.... and the red may be blue on your harness.. etc... not hard really...
the only thing is, you may or may not have to alter the fender, frame, seat, or something to make the tail piece mount...
but.... look at it this way....
Carpy can take bikes from this
http://www.motosolvang.com/images_new/large/1970_Honda_CB_750.jpgto this
http://www.motonews.biz/wp-content/uploads/2009/06/honda-cb750-cafe-racer.jpg... so....
the answer is ...
a definitive absolute positively -yes- you can.... people put tail pieces on these bikes every day... cafe racer or other....
but..... how familiar are you with fabrication? or more importantly, how scared of it are you? because bolts and mounts will not line up... you'll have to fabricate -something- somewhere to make it work, guaranteed...
-Your servant is your master-