Try here:
http://www.tradebit.com/filedetail.php/101743686-yamaha-virago-xv1100-service-repair-manual-pdf
OR
http://store.payloadz.com/details/779458-eBooks-Automotive-Yamaha-Virago-XV1100-XV-1100-Service-Repair-Manual-1986-2003.html
They cost, but should give you a full workshop manual, including the diagram you need