The first thing I would do is to change needles. Bottom Line is a very fine thread and you are using a huge needle. Try a 60 or 70 needle and see if that helps. Don't get discouraged. If a high quality machine is giving you fits, then there is probably a good reason: user error! On a scrap fabric quilt sandwich experiment with changing one thing at a time. Good luck...you will figure it out.
BTW, I use Bottom Line in the bobbin AND on top all the time in my Bernina with no problems.
Last edited by Gabrielle's Mimi; 06-26-2013 at 07:07 AM.