Hi!
But...The bearings must be changed anyway! Just because you can turn the crank doesn't mean the ballbearings turn. I have seen many cranks that just slips on the inner surface of the ball bearing.
Changing ballbearings is so easy and is more or less mandatory if you want an engine to perform at its best. But if you are only looking for the engine to run and don't want it to run good ...then just don't bother....just heat it.