This is a continuation of my series of posts documenting the restoration of my BMW R65. For the previous post, click here.
When we last left off, I had attached the forks and swingarm onto the frame and gotten both wheels back onto the bike. Everything is really coming together and it's starting to look the way it's supposed to! 😁
In this post I'm going to detail the process of constructing the seat, including the upholstery. I'm very inexperienced as far as sewing goes, and have never tried sewing upholstery so please forgive my beginner mistakes. As with almost everything else about this restoration, it's a learning experience.
Construction of the seat began with cutting out the base to which the foam and cover would attach. I drilled holes into a 3/4" piece of birch plywood and attached it to the subframe to trace out the silhouette of the seat. Some quick cutting with the bandsaw and sanding the rough edges gave me a finished seat base. I painted the base with black Rustoleum paint.
For the main padding layer of the seat, I used some leftover 2" Kaizen foam I had left over from another project. Kaizen is closed-cell polyethylene foam which is very firm, generally used for multi purpose storage. Using 3M adhesive spray, I attached the foam to the wooden base and cut it to shape.
To cut the contour of the foam, I opted to bolt the seat to the bike and shave foam off until I reached a comfortable shape. I didn't do anything complex, mostly just rounding off and tapering the corners so everything looked good.
The last layer of foam I added before the cover went on is a 0.5" polyurethane foam. This foam is very soft and squishy and provides a thin compressible layer for added comfort. I traced the seat onto the foam, cut it out, and stuck it to the Kaizen foam with spray adhesive (no picture, but you'll see it later).
The cover was made out of black vinyl fabric. I selected the "arctic vinyl" option since it supposedly is more resilient to colder temperatures and will resist cracking. My original plan was to sew a layer of 0.5" polyurethane foam in between two layers of vinyl to create the cushioned diamond pattern for the cover but our sewing machine isn't robust enough to go through such thick material, so I settled for a layer of quilting batting between the layers, and it gave the same kind of effect. Not as much texture as I would've liked but the effect is still nice.
I again traced the seat onto this diamond-patterned piece and sewed along the line, cutting it out to shape. I then took a "negatively-shaped" piece of vinyl and sewed it to the main piece backwards, such that when pulled out it would fold around the sides of the seat and could be stapled into place. The sewing machine skipped a lot of stitches in this step, since I was working with a lot of thick layers. Because of this, I had to go over the line a few times in places to make sure it was all secure. The end that meets the gas tank needed a connecting piece to form the corners, which was simply sewed into place.
Once the entire cover was sewed together, I sprayed the middle part with spray adhesive and stuck it to the urethane foam, if for nothing else than to keep it centered and in place for when the rest of the cover got pulled and stapled into place. That said, I unfortunately got so caught up in the act of stapling the cover on that I hardly took any pictures of the process. But as you can imagine, it involved starting with stapling the front of the cover down (pictured below) and working down the sides to the back, pulling everything even and making it nice and tight.
First you start with a few staples.... and blammo you're done!
And with that, it's done! I've gone out of order with these posts compared to the actual progress I've made on the bike, so for now I'm not going to show off the rest of the bike until a later post. When that time comes, I'll show some other angles of the seat. Overall, I'm incredibly pleased with how it looks, and I learned a lot along the way. I may redo the cover later on just to give it a nicer cleaner shot but for now I'll move on to more important parts of the restoration.
Thanks for reading,
Juju