WARNING: If the handlebar clamp in not tight enough, the handlebar can slip in the stem. 
This can cause damage to the handlebar or stem, and can cause loss of control.
-Tighten the bolt(s) of the handlebar clamp
-If the handlebar clamp has more than one bolt, tighten the bolts equally.
5.Test the tightness of the stem:
-Straddle the front wheel between your legs
-Try to turn the front wheel by turning the handlebar
-If the handlebar and stem turn without turning the front wheel, realign the stem with the wheel
-Tighten the stem bolt(s) tighter than before (about 1/2 revolution only at a time)
-Do this test again, until the handlebar and stem do not turn without turning the front wheel.
6.Test the tightness of the handlebar clamp:
-Hold the bicycle stationary and try to move the ends of the handlebar forward or backward
-If the handlebar moves, loosen the bolt(s) of the handlebar clamp
-Put the handlebar in the correct position
-Tighten the bolt(s) of the handlebar clamp tighter than before
-If the handlebar clamp has more than one bolt, tighten the bolts equally
-Do this test again, until the handlebar does not move in the handlebar clamp.
7.Put the handlebar parts in the correct position:
-Put the brake lever and shift control in a position that is comfortable to the rider
-Make sure the brake levers do not touch the grip or the shift control during use
-If you have a grip shift control, the clamp screw for the control is in a recess on the side on the end nearest the stem
-Make sure the brake levers do not touch the grip or the shift control during use