Creating 3D models of discontinued parts

I own an Honda NTV650 Revere, year 1991, and I still use it regularly after 33 years and 254.000 km. The bike has been kept in perfect working order for all these years thanks to the availability of original spare parts, a true Honda excellence.

Unfortunately some parts are no longer available and even the second-hand market is not well stocked for a model that has not had a large diffusion like the NTV650. In some cases 3D printing of plastic parts can be a good solution. I recently made two simple parts that are no longer on the market, the price of 3D printing at specialized services is now affordable, to the point that the cost of the two spare parts printed in nylon was 10 €, while the original Honda spare parts would have cost about 35 €!

The Honda 42120-MS9-000 spare part is a very simple object; just a plastic cap used to cover the wheel center hole. The part 3D printed in nylon is more robust than the original, painted with a plastic primer and aluminium color is a very satisfactory solution.

In the photo, from the left, you can see the original part, the object as it exits from the 3D printer, and the object once painted.

This is how the part is rendered into the OpenSCAD 3D CAD Modeller:

And this is the 3D file: Honda 42120MS9000 STL.

Honda does not produce the fuel cock lever (16965MM5770) any more, nor the fuel petcock (16950MS9005). If you need to replace the petcock you can find several non-original spare parts, but every item I found has a noticeable difference: the square pin where the lever is mounted is shorter than the original: 5 mm instead of the original 13 mm:

The original lever does not fit the non-original petcock, because it interferes with the metal body. So I drew in CAD a modified lever, which will stay in the correct position once mounted on a short-pin petcock. Here you can find two 3D projects: one is like the original part, the other does fit a 5 mm pin petcock.

WARNING: The original lever have a metal inner core; my project features a 7.0 mm inner hole, so you have to fit a piece of metal tube in it, see the picture:

The screw is 5 mm, a tube with diameter 7.0 x 5.4 mm (outer x inner) would be the optimal, if you can find it. I inserted the little tube just by pressing it; the 3D printed hole provides a bit of interference.

In this photos the 3D printed lever with the metal tube (7.0 x 5.4 mm diameter, 6.0 mm long) and how it compares witht the original part:

This is how the part is rendered into the OpenSCAD 3D CAD Modeller:

Download the 3D file: Honda 16965MM5770 STL.

This is a slightly modified project, designed to fit petcocks with a 5 mm long pin. Here you will need a metal tube (7.0 x 5.4 mm diameter, 13.0 mm long). Generally these non original petcocks have the pin smaller: a square section of 7.60 x 7.60 mm instead of 7.90 x 7.90 mm.

Here it is the 3D file: Honda 16965MM5770 STL, modified for short pin.

This is the cap covering the swing arm pivot of the Honda NTV 600 and NTV 650 models:

Download the 3D file: Honda 90302MS9000 STL.

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