BB - don't recall exactly but don't think so. When new it went on my Kadet Senior kit. It was torn it apart as part of clean up following demise of the Kadet. I've had it on several other planes since. Bearings have been replaced. What I'm saying is that I've gone thru the drill several times with this motor (and every other 2-stroke & 4-stroke) that I own. Just consider it to be standard setup. I fly at nearly 6000 feet. No manufacturer's initial settings work without tweaking.