How can I tighten the stem?
 

I just bought a new bike. It's an 08 Diamondback Response Sport. It's not really broken in, but I'm having a small pop sound with it...

If I hold the bike upright and apply the front brake and push the bike front/back, I hear the pop sound. When I place my hand on the headtube (where the real steering action happens) I can feel that the pop is happening within there.

I DO have a warranty with this bike but, the bike shop is like 35 miles away... so if this is just a minor adjustment I can do myself I'd rather do it. Thing is, I'm not entirely sure where I'm actually working with this.

Here's two pictures of my bike, close up to the area I'm talking about. I'm linking these just so you guys can get an idea of what I'm looking at.

Side View:
http://s2.photobucket.com/albums/y36...t=P1080110.jpg

Top View:
http://s2.photobucket.com/albums/y36...t=P1080111.jpg

Note - Particularly at the top "ring" of the headtube, right above where you see (on the 2nd pic) the strong box logo, that's where I can feel the pop the most.

My buddy suggested I need it tightened. If I could avoid a decent drive to get this adjusted, I'd be happy. If this is something that a novice like me just shouldn't be messing with, feel free to tell me so. :)

Loosen the two pinch bolts that tighten the stem onto the steerer tube.

Now tighten the allen head bolt in the round top cap of the steerer tube until no play is felt when you rock the bike with brake on.

Now tighten up the stem clamp bolts to lock in this adjustment.

Just one addendum:

If the front wheel can't readily fall to the side (L/R) after tightening, it's too tight.

-Roger

Nice! Thank you both! It's spinning freely to each side and has no pop sound now. Awesome.

+1 Yes, the handlebars should flop over to one side or the other when you lift and tilt the bicycle. But there should be no play when you rock the bike. To test you hold the front brake on the wheel. Now, while applying the brake, hold the bike by the stem or the top-tube and push it back & forth. Any play? Tighten the top-cap a little more. Keep adjusting to find it's "sweet-spot" of no play and wheel/handlebars flop to the side when tilted.