Ok. first let me acknowledge the bike I have is a POS. So those who want to call it out... I already know it. Planning on getting something better once the snow is gone.

In the meantime I have this Mongoose XR250 bike.

Looks like this one....

I am riding it indoors on a magnetic trainer..... the last couple of days it has been making this popping noise and I know its from the crank area but not sure what it is and if its something thats an easy fix or not.

I don't have any LBS near me... would have to drive to one in a different town.

Here is the sound: http://www.knackjack.com/bikepop.wav