By your dims you have .002 thousandths of an inch clearance ,that's fine ,what your issue may be is the pinch is still too tight ,the engine will bog and run hot until it is run in correctly. You will need to "run it in" all over again after a pinch especially if it is a tight one !! Also this will definately stress out the rod too.
At 1.5 gallons why did you pinch it !!! I think you may have a tune issue .
EVERY Novarossi based engine I have ever seen or tuned took that much fuel to "run in " correctly ! Anyone that says it can be done in 10 or 15 tanks is either lucky or Lying ! And RB's are no different as they are Nova based .
It takes time to do it correctly period !! And it only takes 1or 2 tanks too lean and you have ruined your piston/sleeve ,thus a re pinch is in order.
So take your time ,run it in correctly and it will come round !