Seat Options and Issues

Yamaha AS1 seats are rare – silly rare, in fact – and even a so-so example commands serious money. The foam is first-generation stuff based on an expanded, foamed, natural rubber that has an open cell structure – read sponge. Water inevitably gets in through the cover’s seams and then rots the base away thanks to its inbuilt water source.

Many AS1 restorers find themselves going through numerous decrepit seats before finding one that’s strong enough to take some therapeutic welding. This project is on Seat Base No.2, which definitely has some rot in it. The ‘foam’ has hardened and the cover is split, so it’s not going to be an easy fix.

The pattern seat cover I bought from Thailand turned out to be 45mm short so that’s no use either. Now factor in that no one makes a pattern seat foam and it’s all getting rather frustrating.

Yes, fibreglass resin could be used to reinforce the steel base but I feel that’s more of a bodge than a repair. What there needs to be is a gentle and sympathetic blast clean, and not shot through with holes.

And, of course, I still need a decent, viable cover... and this is where many AS1 restos fall over; the cover and its shape are singularly unique and a bad cover/foam combo can ruin the side-on profile.

Therefore, and in a decidedly atypical fit of munificence, I shall be farming the job out to an expert who understands Japanese motorcycle design and aesthetics!