So over the last 8 months or so I have been in the process of rebuilding 1978 JCPenny Pinto which was manufactured by Puch/Kromag. (Don’t worry, there is a post still to come covering the build!) Well when I bought it it was about 65% complete and in need one of the most important items– a seat.  I decided it would be a fun project to fabricate my own in the Cafe Racer style, but that still complemented the lines and shape of the original bike.  I luckily came across an old Puch Magnum trunk, which is the Pinto’s big brother, and thought it would make an awesome starting point. It maintains the style of an original Puch race-stlye rear fairing and technically is OEM (Right?). Since the Pinto is significantly smaller than the Magnum I figured that by cutting down the depth of the trunk it would help maintain proper ratio for the bike. Then my next step was to create my shape; I used the width of the trunk for the rear and then tapered it  towards the front with a curve to mimic the front of the gas tank. I mocked up a cardboard template to see how it may look and was pleased with the feel.

After cutting down the trunk I wanted to fill in the hole where the trunk door would go. I thought it would be cool to still keep its original  functionality, but to switch it up a little. Originally the Magnum would have a door that enters the trunk from the rear; well first off I didn't get that piece when I sourced the trunk and secondly I thought it would be a little sleeker if the fact that it was a trunk was hidden. Since I planned on making the upholstered seat-pan section removable from the seat I could create the entrance to the trunk right underneath it.  So I created the shape to fill the void and cut out a piece of 1/8” ABS to fill it in. I scored the side I was going to be adhering for a better connection, as well as placed ridges around the perimeter to keep it from moving at all once it was in place. I then taped the piece flush and used a hard silicone sealant and filled it all in from the inside. After the sealant dried I took off the tape and then proceeded to use some Bondo (for bumpers!) to plane the outer surface of the trunk. Once I was satisfied withe the shape it was painted, primed, and clear-coated to match the rest of the bike.

Then my next task to create a base plate to mount the trunk to and furthermore mount it to the bike. This segment needed to be extremely rigid since it was only going to be mounting on the bike by about the first 30% of the plate and was going to be able to obviously support my weight. I decided to go with a 3/8″ piece of aluminum that I could then machine the base from.  I then cut out my shape with an angle grinder and then proceeded to machine 1/4”  standard round perforations to lighten the plate. I also created 5 larger holes; 2 to accommodate for travel of the gas canisters on the hydraulic rear shocks I was going to be using for the build, as well as one in the center for the end of the seat tube and 2 in the trunk section for more weight reduction.

I then had to fabricate the ‘butt-stop’ which would transition the bottom of the seat plate 90 degrees to the top of the trunk. For this I needed a much thinner material and found a piece of 16g stainless steel sheet that was perfect. after cutting and rolling my piece from my template shape I cut a hole in the center of it with a torch for entrance to the trunk. Since the upholstered seat-pan portion I designed to be removable from the base of the seat you can then take it off and get right into the trunk (with just enough room for a few tools and a bottle of 2-stroke oil). The decision then was to figure out how I was going to mount the 3 pieces of the main part of the seat–the baseplate, the butt-stop and the trunk–together as one. I thought that rivets would look the cleanest and most professional as well as would maintain a flush detail inside and out. So I proceeded to ‘tack’ the three pieces together and riveted it all as one, using 90 degree mending braces to mount the butt-stop to the trunk.

Now it was on to creating the fiberglass seat-pan that would sit over the base that would be then padded and upholstered. I first mounted the seat on a sawhorse to better work with while fiberglassing, and after smoothing all the edges with some card stock I sealed it up with a sheet of adhesive vinyl to keep all  epoxy off the physical seat, then it was time for glassing.  After it dried on the mold for a couple days I removed it and cut the shape down to size with a dremel. After it was cut down I used some industrial strength velcro to connect the seat-pan to the base while maintaining its removability to access the trunk.

So far I am more than pleased with the result. The lines flow perfectly with the original shape of the bike and the  usefulness of the trunk has proved to be more than practical. However I am unfortunately at a point where I need the last few steps of the project, padding and upholstery, to be done my a professional. I sourced some leather at a fabric store and found a custom fabricator to do it. So I sketched up my idea of the design and look forward to getting this finished real soon.

So stay tuned to see the finished project!