po18guy

The chain is 525 size, 92 links. 525 chain is now considered a quite heavy-duty size, and one can obtain an O-ring type that will last forever on a YDS3. As to a manual, I can only suggest eBay. Alasdair at YDSparts.com might also know of a source. Here's US site that is dedicated to old Yammies: http://www.vintage2strokes.com/index.html Cheers, as well.