I recently purchased a Fuji Team 08 bike. It comes with Shimano 105 FlightDeck shifters (3 gear shifter) and a Shimano 105 derailleur (with only 2 gears in the front). The problem I have is this: When I try to shift to the larger gear in front, I need to move the shifter two clicks and often the chain will fall off (goes past the large gear).
The other problem I have is when I'm in the large gear in front and I go to the second smallest or smallest gear in the back (total of 9 gears in the back), the angle in the back will cause the chain to fall off the large gear in the front.
How should I tune the derailleur or the front shifter to fix this? I can take it back to the shop and have them do it for free, but I have to schedule it and they were having problems doing it when I bought the bike (from Performance Bike). Does it simply need to be tuned or is there a faulty part somewhere here?