See the illustration I added above - this Neutral-to-Ground bonding plug is made from a hardware store 15 amp plug. No disassembly of the generator is required.
Insofar as the advisability of bonding Neutral to Ground, I would refer you to the following
ARTICLE. On my Yamaha generators, it doesn't matter which generator the Neutral-to-Ground bonding plug is plugged into since the two generators are tied together at the 30 amp receptacle. Your Honda generators use a slightly different paralleling system since the 30 amp outlet is on one of the generators, so I might plug the bonding plug into the generator with the 30 amp outlet, but it probably won't matter.
Rusty