1981, 84, 88, 89, 94.

81 beat the Bengals, 84 beat the Dolphins, 88 beat the Bengals again on the Drive, 89 beat the Broncos in the most lopsided SB ever (55-10), then 94 was Steve Young's win over SD.

There mighta been another win in 83 if not for a horrible PI call on SF in the NFC CG against Washington, which the Niners lost on a late FG 24-21.
Niners are 5-0 in SBs