Janome MC9700 bobbin rattle

Question

When I sew FSLace the machine is very noisy, I think it could be the bobbin or bobbin race rattling. Have had it back for service (its only 10 months old) but no difference. Normal sewing and embroidery is fine, its only when making lace. I take the plate off and bobbin race out and clean often but the problem starts again after approximately 2 minutes of sewing.Toni