Yes, you must continue to honor them and treat them with kindness; a non-Muslim parent's rights of good treatment do not end when you become Muslim. When Asma' bint Abi Bakr asked whether she could keep good ties with her polytheist mother, the Prophet (peace be upon him) told her, "Yes, keep good relations with your mother." The one limit is obedience: if a parent orders you to associate partners with Allah or to commit a sin, you do not obey in that specific matter, yet you still accompany them in this world with kindness (Quran 31:15). So obey and serve them in all that is good, and decline gently and respectfully only where it would mean disobeying Allah.
Evidence — the daleel
On deen2u
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.