Here's the recommended list of plumbing parts you'll need to complete the installation:
Parts List
Bulkhead Fitting
The most difficult part of the installation: you must remove the sending unit plate in your stock tank and drill a hole in EXACTLY the right place for the bolt-on bulkhead fitting to clear the working parts of the sending unit and gasket area.
Removing the lock ring is best done with the special Honda OEM tool and a 1/2" drive breaker bar.
It is critical that you measure twice and drill once!
The fitting shown in the photo above is welded on and the location for the bolt-on fitting is left of what is shown. The large o-ring-washer underneath the fitting fits just under the back of the sending unit bracket and inside the gasket area (you can see the sealing area of the o-ring on the bottom of the plate once you get it off and in the photo below). On '06 plus model years you will most likely have to carve out part of the fuel tank, inside the gasket groove, to make space for the large nut on the bulkhead fitting. The fitting must go on the low side of the plate to allow the seat hook to fit back under the rail.
Mounted location of a Sampson Bolt-On Bulkhead fitting, top view. Note how close to the white connector it is. This is the 5/16" fitting. The 1/4" fitting is easier to install and will transfer fuel plenty fast enough.
See Below.
Underside view of a Sampson Bolt-On Bulkhead fitting without the nut installed. Note how the washer is tucked in under the float bracket and has been trimmed on the outside to allow more clearance for the gasket (gasket line is about 3/16" inside the outer edge of the sending unit plate.
NOTE: This fitting is not designed to be very tight. The nut should only be snug when installed. Follow the instructions that come with the fitting.
You will most likely have to trim a notch in the fuel tank opening, inside the gasket groove, to make space for the bulkhead fitting nut.
A Dremel tool works well - stuff a rag in the tank to catch the shavings. Do not trim into the gasket groove.
It will be much easier to use the 1/4" Bulkhead Fitting from Sampson.
You will not have to carve a notch in the tank, but you will need a foot of 1/4" hose, two more hose clamps and a 1/4" to 5/16" Hose Barb Adaptor from fastfittings.com
This photo shows the diffence in size between the 1/4" and 5/16" fittings.
First, clean the sending unit plate with a wire brush as necessary.
Use the large washer to mark your drilling spot on the top of the plate.
The spot to drill is 0.40" from the electrical connection.
Center punch your mark. Start with a nice sharp 1/8" bit for a pilot hole. You may then want to drill with a 1/4" bit before you open it up to the final size of 7/16".
This is what it will look like after you drill to 7/16" for the 1/4" Bulkhead Fitting.
Deburr the hole on both sides. Making it a smooth as possible to avoid damaging the rubber o-rings.
Mount the 1/4" Bulkhead Fitting and tighten the nut on the bottom while holding the fitting on top by hand.
Align the nut so a flat is facing the gasket area. This will allow maximum clearance to the edge of the fuel tank opening.
While holding the large, bottom nut with a wrench, tighten the top side nut until the fitting is tight. Not so tight that you squeeze out the o-ring.
It should look like this when you get it all together.
Attach the piece of 1/4" hose here and put your 5/16" Barb Adaptor along the frame.
An alternate method that will allow you to avoid trimming the tank is to glue the bulkhead fitting in place with JB Weld, QuickSteel, or some other fuel impervious adhesive.
This method also allows for some deviation in the mounting location.
Top View.
Glued in Bulkhead fitting.
Bottom View.
Line Routing
Route your new fill and vent lines as follows:
First mount the fittings to the tank with a very short piece of hose to the the fill disconnect and a longer one to the vent disconnect (long enough so the disconnect does not rub on the tank).
Secure the fuel line from your new bulkhead fitting to the frame.
Route the fill line so it follows the frame and exits beside the seat at the location of the fill disconnect.
Run the vent line behind the rear fender and under the trunk. Secure it to the subframe.
Exit the vent line between the seat and trunk pocket.
Disconnects shown here are Chrysler Marine units. The Sampson units are smaller, but this is where the disconnect should lie when the seat is reinstalled.
When the tank is not installed you should cover the disconnects with something like an old film bottle to keep the dirt out. Punching a half inch hole and making a slot in the film cap makes this easy.
Here's the recommended list of plumbing parts you'll need to complete the installation:
Parts List