Ok, I'm kinda new to adjusting my bike but i have a problem with my handlebars and/or stem. I tighten my handlebars everytime before i go ride, and whenever i hit a few jumps and bunny hop around a bit they always budge forward or backward. I have taken them down to my local shop several times, but they have never been able to really fix them. My friend and I suggested spraying hairspray on them, wait for it to dry, then put them back on. What do you suggest? Thank you.