Yes, i'd like to know more about the J3 aswell, i can not find any info on it anywhere, not even on the RB site.

My father is having all sorts of dramas trying to run it in (sticking to the instructions) It gets hot (not overly) but mainly because it won't run long enough.
We aren't sure if its a engine problem or an issue with the clutch on his new Serpent 720
We havn't had this problem before with any OS or Novarossi engine we have. Only with a Collari that we would get it tuned well, run one tank through it, then the next it wouldn't run. It was the hardest to tune motor we have ever come across.
We eventually shelved that motor