What i was trying to do by asking this is two fold. I don't doubt that brendan is the knowlegeable dude and even if he's right or not.
Im trying to figure out what is on my bike , just for shits and grins.
Secondly, this points out a SERIOUS case of lack of empirical knowlege about what is , after all a very very common motor. Its a 505 for the love of god, they made a ton of em. But service manuals and actual data is very difficult to find if it can be found at all, and people do have different thoughts on the matter.
Odd isnt it that there is no manuals out there?
I have a 504 manual, and it lists every variation of the motor, all 5 of em and the technical data reflects what the differences are, from carb and jet sizes to exhaust ports.
It would be cool to have that written out for the 505.