Bonneville seat?
Answers:
Try here for a second-hand one -
http://www.partfinderuk.co.uk/
Or here for a Corbin seat -
http://www.battistinis.co.uk/
Call around to local salvage yards, give them your make & model, and ask how much they'd charge for the seat. You'll have to go pull it yourself or take a friend to do it, but it's way cheaper than new, and you don't get screwed by ebay's anonymity & third party crap.
You should be able to find listings in the Yellow Pages under Auto - Auto Salvage, etc. If you can't find a phone book (I say this because we have like 10 around here & never can find a new or local one), try http://www.switchboard.com
I don't know the situation you and your seat are in. Get it reupholstered?
using your single seat i can attatch a pillion and make a dual seat for your triumph. www.vikingvinyl.piczo.com
breakers yards would be your best bet and there are a few good ones on the web that give you an idea whats on stock. this would be a hell of a lot cheaper than buying a new one or even a custom one and have you tried www.bonnevilleowners.com . ps nice choice of bike.
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