My apologies - I know that this has been done to death.... 1980 XS650 Special II. Just reassembled after changing the front cam guide and tried to adjust the tensioner. Haynes says tighten it until the rod is flush with the top of the threaded piece. I do that but it feels way tight, so I remove the tensioner to take a look. When the rod is flush with the top, there is zero travel. The nose is bottomed out. So I reinstall and adjust so that the rod is 1 mm below the top and does not reach the top as I spin the engine. I figure that I am OK here, but what the heck? I've seen on the forum that the rod should be 1 mm proud of the top, but that would not work here either.