This is NOT where you time these machines!That adjusts when the hook starts it foward motion in relation to the needle. Look behind the round front plate on the lower rightside,you turn the machine so the needlebar is about an inch into the material & you'll see a 6mm allen in there.THIS is the timing adjustment for the hook.Lower the needlebar down all the way & turn machine handwheel towards you until it rises 5.5mm the the point of the shuttle should be @ the needle & approx a good 1/8" above the top of the eye of the needle.Like Rockyaussie mentioned check to see if the bar got pushed up first b4 you start adjusting the hook! Look @ screw #2 in the attached file.This is the one that is attached to the hook driver & the only way to adjust the timing.So re-tighten your other screws ,your machine should be OK & just use this method for re-timing.
CB441 manual pg8.pdf