My FW came with a factory receiver hitch, but like most, it is only rated for 300#s. It is well built, but I'm thinking the FW manufacturer, just does not want any more weight added to rear, which takes away from the pin wt. I also bought a nice well designed motorcycle carrier to fit in the receiver, for my 250# wet wt dirt bike. The carrier sticker says "not for FW, or TT use", but fine for MH or truck receiver. I double tow instead, with bike trailer, for my crotch rocket, and dirt bike.
IMO, the bike wt you are talking, is not going to work on trailer rear, but may work on truck front receiver, depending what it is.
Jerry
