Riders on the 43-Masonic got a shorter ride than expected Tuesday afternoon when the smoke was spotted from its rear forcing the coach out of service.

According to San Francisco Municipal Transportation Authority spokesman Paul Rose, smoke was reported coming from the rear of the bus around 4:30 p.m. at Presidio and Geary avenues, nearly three-quarters the way through the inbound lines route.

The reason for the smoke is unknown, Rose said.

Rose said the bus was immediately taken out of service. No injuries were reported, Rose said.

akoskey@sfexaminer.com