Recently I changed the spark plugs.
Upon installation, I tightened them fairly by hand, but not too much.
After riding a bike for few days, I went to check them and found out they were loose. By loose I mean they could be unscrewed easily.
I suppose it happened because I tightened them while they were cold, then they expanded during riding, then shrunk again after cooling.
My question is, should I re-tighten them now, while they're cold? Will they cause problems once they start expanding again?