Fibreglass Cafe Seat Build

I've been meaning to document this progress here for quite some time but never seemed to get around to it. A couple of questions from XL777 gave me the push, thanks.

Back in October I picked up a 1978 KZ650 D1 with the plans of cleaning it up and making a cafe racer out of it. The bike wasn't in too bad a shape but definitely needed some TLC. This post will just be about the process I went through making the cafe seat.

First off here is a pic of the bike as it was when I bought it. Check out the "custom" seat! No matter how mine turns out it can't be that bad...can it? No where to go but up

Underneath the seat cushion was a really rusty seat pan. The top was fine, but the edges were totally gone. I wasn't
planning on using it anyway, so no loss. After that was tossed aside, I just had to grind off a few things: seat hinges, seat lock and helmet hook had to go.

To get the shape I wanted I used a combination of green florist foam bricks and Great Stuff expanding foam. If I had to do it again I wouldn't have used the expanding foam, as I didn't like shaping it at all. In contrast, the florist foam is a dream to shape, it cuts and sands easy.

After cutting and shaping I ended up with something that I was happy with:

Next step is getting ready to fibreglass. Before applying the fibreglass I needed to seal up the foam. I used a combination of foil and painter's tape. Since the strength of fibreglass is in the curves, I built in some curves to the seat section. Problem is that I forgot about the battery box that would be underneath the seat. So I later had to change this section to accommodate. You'll see this in later pics.

Time to get messy...lay some fibreglass. Not much to say just make sure you have everything ready before you start: fibreglass mat all pre-cut and layed out, anything you don't want resin on covered up, gloves on, and most importantly put your mask on, you don't want to be breathing these fumes. I know I can't afford to lose anymore brain cells You can see in the last pic the modification I needed to make to the seat section for the battery box.