Originally Posted by
02Giant
Not knowing the sequence you are using to tighten the clamp bolts, I would caution against tightening either the upper or lower fasteners, then the other. Snug them evenly maintaining as equal distance between the faceplate and the stem body before torquing to the final value.
If you would look at the side profile of the stem with the cap seated and no bars in place, you will see the opening/machining is not concentric.
Turns out, because of a light mounted on the bars, I got the left /right location a little off-center so we had to do it all over again - this time paying a lot of attention to balancing the four bolts during reassembly. The big plus is that my son - at this point - was very focused on the issue so I let him do it. It should give him confidence and also give him the knowledge to check the bar on his own. We painted the bolts so he can see any movement, and he's taking my torque wrench so he can test it over time (at a lower setting) if he wants.
We also checked the bars for damage (which I never suspected anyway), used the carbon paste and loctite.