Well. Right now, there are a lot of problems with the motors that BGF gets. Other vendors also get motors from the same factory that BGF gets engines from. I believe that the connecting rods are fine on the complete engines. I only had bad connecting rods from the replacement bottom end units. But the story gets more complicated. For starters, I'm not happy with the balancing work that is done to the crankshafts on the BGF engines. They are not adequately balanced for high revs. Also, more recently the factory decided to change their source for the magnets for the ignition. These magnets can be indentified by looking at the thickness of the metal plates which make the magnet. They are thick (about .030" thick). The old, good magnets have thin plates (about .010" thick). Not only are the new magnets weaker, but worse is that they are 10-20 degrees advanced! I tried one of them and I couldn't even keep the motor running.
My personal favorite PK-80 motors come from DAX. They are called the type D motor. Some of their type D motors came from the same factory as the ones that BGF gets, which I'm not crazy about. The ones I really like are the ones which are put together with black socket cap screws. I'm sure you can request that. Those crankshaft are better balanced, and they do not have the crappy magnets.
-Fred
