Warning, my VN700 had these plastic funnel types and they had, over a period of time, basically melted and become deformed. The plastic nipple at the base of the funnel was bent almost to a 45 degree angle. I think the previous owner installed them and never noticed that they were losing their shape. Keep them away from the cylinder heads, plastic melts when in close proximity to a heat source!
I am sorry that I do not know how long they were in there and my engine always runs hot, so you might be okay with these but I would go with the metal ones referenced by KnifeMaker for an application this close to the cylinder heads.