I'm almost positive there isn't an o-ring there, sure hope not at least b/c I've never put one there lol. Any way you can post a pic of the manual and the figure in question so we can see what you're looking at?
looks like standard direct drive style lockup. lots of people run them and love them. i know several guys that run them on their bikes and havent had any problems.
try this link lockup
I've never had Jeff do any motor work for me but I've seen some of the bikes he's built run and they're not slow. Buddy of mine had HJR dune port and it ran really good too. Just another opinion.....