I just called the number that Maux provided and I accidentally asked about the ferry from Dalian - Yantai, not the one to Wehai. Just bought some Yantai apples from the supermarket and it must have stuck in my mind.
Anyway, here's what I just discovered about the Dalian-Yantai ferries:

Dalian – Yantai (6 hours, roughly)
08:30
14:00
20:30
22:30

Yantai – Dalian (6 hours)
09:00
12:20
20:00
22:30
23:50

165rmb per person
Motorbikes are allowed on, no problems there but after being redirected through three numbers there was nobody who knew the price (although I bet Maux's info is pretty standard for most of those ferries) or could tell me how the bikes would be secured to the deck. The last woman told me to ask the workers on the ferry for that info before hanging up on me. The first woman was the rudest of all though, probably because she was with the Weihai ferry and didn't have anything to do with the Yantai ferry that I asked for.