matthew stott , Sep 28, 2009; 11:17 p.m.
My caveat: I have never worked on a Yashica, but most of these shutters are the same.
The first thing I would do is to remove the self timer assembly. To do this you need to remove that big spring (be careful!), remembering what posts it connects to. Then you will need to remove either one or two screws (each timer I have seen is different, but they all had at least one screw- never more than two. These screws are often behind the lever you pull down to set the self timer. It should lift straight out pretty easily.
Anyway, that blue triangle is the clutch mechanism, it prevents the timer from spinning backwards. Here are the parts inside (or at least a close enough copy): http://i4.photobucket.com/albums/y118/mstott/ikoflex%201a/iko-outoflens.jpg
The camera should work just fine without the self timer- so if it is jammed you can just remove it. Or remove it and fix it separately.
As for the bulb problem- you had to remove a steel cover with cutouts to get to the shutter/timer works. It probably looked something like this guy (your yashica ring may not have the numbers on it):
There are a few posts you have to line up properly to get it to work. Two of them are near the numbers in my photo- near the 2 and 1 second marks. The third is the tricky one. It is in the long, thin slot near the top left of the photo- you cannot see it in my pic. This tab needs to be in that slot, and if I remember correctly, it was tricky to get it into the slot. This tab is what messed up my bulb settings (again, it has been a while).
Would be happy to stand corrected, if you have not already found Rick Oleson's site you should definitely look it up.