dang. that's unreal that you can't just buy an oring.
I just ran into that problem sorta w/ the wifes motorcycle. headlight went out mid last week, I got off work early on thurs to ship some stuff out and I figured I'd hit up a few places to see if they have a bulb for it. (sealed beam headlight)
went to an auto store they said no.
went to a local motorcycle place, they said no and that only a dealership would be able to order it
went to the local yamaha dealer. Looked it up, none in stock. Asked if they could order one.. the guy laughed and said... Im assuming you don't want to order one. I asked why?
for a new headlight off a 1980 XS400..... $120 for a light.. are you kidding me?!!!
so me being the handy person I am. I tore apart the bulb. Which is the same connection as an automotive H4 bulb. And got it working again... $6 and about 1 hour of time taking it apart and making it fit. vs $120.. aww yea!