the bike in question, would be modified partial streamlined pushrod gas or fuel [depending what's in the tank]
things that make it modified would be the rear chain, exhaust ect, once you modify the bike so it is no longer classes as a production / production, [frame / engine] the modified rules apply, including the partial streamlined rules.
I thought about just pulling the rear inner fender off my Buell to go after some modified records, but would then be classed partially streamlined unless I take the little OEM windscreen off.
its actually cut and dry.
any and all questions are answered