I want to use the oil injection system on the RD400 café racer (/chopper)—meaning side covers have to stay. Due to that, I might as well run a regular sized battery. The problem is, the stock battery box mashed the top of the battery up against the seat. So I cut the bottom off and welded in a 1” piece of steel.

Speaking of that, the stock oil tank uses a filler tube inside the frame rails, meaning the seat had to be lifted each time the tank needed to be filled. My seat bolts down, and though honestly, the tank doesn’t need to be filled THAT often, I didn’t want to unbolt the seat.

Anyway, I chopped about an inch off the stock filler neck, and welded on a fender washer. Pretty shit-looking welds, but no one will ever see it. Since I welded over the original filler neck, I needed some way to fill it with oil. Enter the weld in bung with the aluminum cap. However, before I could weld it in, I sanded off the original paint (we mustn’t weld through paint and oil now), then marked where I wanted the bung to go. Finally, I drilled a hole. I didn’t have a hole saw big enough, so I drilled out a 1” hole and used a pneumatic sander with a ¾” abrasive wheel to finish it out. So now it sits nice and flush.

If you look closely, you can see a part where I screwed up the weld, which kinda pisses me off. This bike will be the anti bondo—though obviously some will be required to smooth out the tins. But no bondo will be packed into the welded. It is what it is.