They show up on Ebay periodically and be prepared for a bidding war. I came to my senses in a shaky, feverish cold sweat on one auction as the price was heading north of $225 - I paid less than that for the whole bike. A company called "Triple-A" made the best of these, at least for my 90 CC bikes. Run an EBay "Followed Search" and one will eventually be found.
Rick