Saw this on EBay. Looks like the entire unit bolts to the rear dropouts. I want one.
http://cgi.ebay.com/ebaymotors/1948...ters_Mopeds&hash=item3381612a7d#ht_500wt_1182
http://cgi.ebay.com/ebaymotors/1948...ters_Mopeds&hash=item3381612a7d#ht_500wt_1182