
Here is the finished oil line. We left a layer of blue tape over the top half of the line to protect the chrome finish.
Despite the popularity of custom bikes in the last 20 years, and the enormous amount of parts and pieces readily available to build the bike of your dreams, there are still some items that you'll have to modify on your own to achieve your desired results. Take, for instance, our friend Chuck. He rides a mildly customized Dyna and somewhere along the line-between reading magazines and checking out events-got the bug to build a bike from scratch.
Like many people who embark on the task of building their own motorcycle, the budget plays an important role in the build process, along with the vision of the end product that drives one forward, especially as the big pieces are bought and assembled. Progress slows up as the details need to be worked out, and inevitably some problems need to be handled outside the pages of a catalog, such is the small issue we will solve here.

Here is our solution for adapting a stock oil line to a braided steel line fitting. The stock line, 1/8-npt coupler, and the fitting.
Chuck purchased a later model H-D Softail oil tank with press-in plastic oil line fittings. The tank came with the oil lines...nice score. The problem arose when Chuck went to plumb the tank to the engine. His engine was not a late-model Twin Cam, but an earlier-style engine based on the Evo-style cases, with an Evo oil pump and oil filter set-up. Oh, and by the way, Chuck spent a chunk of dough on chrome-plated fittings and braided oil line, adapting the stock oil lines to the braided steel fittings. The rest of the oil lines were no problem, other than selecting the correct hose end for the application.
The oil line in question is the return line from the oil filter to the tank. At the tank end the standard fit is fine, but on the other end it was designed to fit into a different plastic fitting into the engine case. What Chuck needed was a threaded end on the return line, preferably a female threaded end in 1/8-national pipe taper (npt) to accept the chrome fitting. A trip to our local hardware store revealed an easy remedy in the form of a 1/8-npt coupler in steel.
To make a long story short, we simply bored out one half of the fitting and then welded it to the shortened oil line. Done deal, complete with the satisfaction of solving it outside the catalog.