1974 Yamaha OW13
Featured here is a 1974 Yamaha OW13.  The bike currently belongs to John Riley.  The bike is a work in progress
as it was missing some parts when John acquired it.  
John recently sent some up dated photos of his bike.  He managed to track down several parts that he was missing including:
Titanium Kick start
Sand cast magnesium twist throttle
Sand cast magnesium clutch basket and titanium clutch bolts
Titanium axles, spacers, nuts, bolts etc