Barry, Juice gave you the best tip-just keep running it. I will add this. Be sure to run it on the bench before putting it in a model. I have a 120SP and a 60SP and like them both. I can't say that my 120 vibrates any more than my 60, taking into consideration the increased size of the engine. These engines are what they are. Some like them, some don't. I fall into the former catagory and am willing to break them in ALOT before installing them on a model. I personally would not be inclined to "tweak" the internals of the engine to lower vibration that will likely be reduced significantly anyway when the engine is fully broken in. Most of the running-in time for these engines is to seat and lap those big gears.