bobbin horror

[pinkplasticgun.livejournal.com]

You know the loopy horror of bump bobbin thread appearing on the top side of the fabric , I can't seem to fix it. My tension is set to 0 (the higher the no. , the tighter the tension), i've cleaned everything out. I'm just sewing through cotton.
I'm using a janome my style 28 , so anyone know what i should do ? I don't really have the time to bring it in and have it serviced.

Thanks!