[SyNiSteR]

I can't figure out why my chain/cassette "pops" when I'm riding a wheelie. Everything goes fine for about 20ft, then it just makes a loud pop and moves down a gear. The bike is only about a week and a half old too. Any suggestions on how to fix/prevent this?

 

[Blue Shorts]

I can't figure out why my chain/cassette "pops" when I'm riding a wheelie. Everything goes fine for about 20ft, then it just makes a loud pop and moves down a gear. The bike is only about a week and a half old too. Any suggestions on how to fix/prevent this?

Your derailler cables are most likely stretching / settling in. You just need to adjust the tension on the derailler cable. It's normal for this to happen, especially with new cables (new bike).