Making a tail section for your bike seems like a daunting task without a shop full of sheetmetal forming tools. You may be overwhelmed and start asking yourself questions like, "Do I have enough tools for such a project?" or, "Is my skill level up to par?" or even, "Will friends think my bike looks cool enough?" Well, I can only help you answer two of those questions.
The starting point of many tail sections is the ever present, random garage floor gas tank. Cutting that tank up instead of constantly kicking it around your garage will help the average garage builder who may not have an English wheel or planishing hammer stashed in the corner.
The first thing I’ll do in this project is pick a tank whose shap I like and draw some lines on it to determine what section I’m going to use for the tail. In this particular case, I’m cutting up an old mustang tank and taking some width out of it to make it skinnier. Once I have both halves even, I clean it up inside and out with a paint stripping wheel on my angle grinder and take the pieces over to my t-dolly for some edge flaring. After tacking the shell together, I take it over to my bike to check the raw fit. When I’m happy with what’s what, I’ll finish weld all the tacked areas.
On this particular tail section, I’ve decided to add a little hammerformed piece frenched into the rear. After drawing a few Sharpie lines that I don’t like, I finally come up with a cutout profile that appeals to me. I trace that profile on a piece of paper, transfer that shape to a piece of ¾” MDF board, cut that shape out then use a quarter-round router bit to round over the edges. Using a piece of 16-gauge steel, I use the form to draw a line that’s approximately 1/4” to 3/8” larger than the MDF form. I cut out that blank and clamp it to the form and start hammering. Be sure not to be too aggressive with the first few hammer blows; you want to move the metal slowly so you don’t create any creases or folds. Once I have the metal hammered down to the form, I’ll take it off, check fit, trim if necessary, and weld it up.
Well, there’s my version of the gas tank tail section. Aside from the details added to this shell, it was all done with a gas tank, Sharpie, angle grinders, and a welder. Sweet.
You can see more of Jay's work here: Special '79 Blog