I see what you mean now, I had to go look at my bike. It looks like you'll never get that elbow screwed in or out of there without taking off the inner primary, especially if there's a tube on it and maybe even if not. I kind of wonder if you couldn't crimp it on with a drilled out, cut in half small pattern nut and some sort of clamp or vice grips? I've got a hose clamp on mine but it's mostly hidden by the S pipes anyhow, plus I'm using 3/8" hose. The original hose was a stepped down rubber hose right at the elbow as I remember. I probably have that end of it in the bottom of my spares drawer, if anyone wants to see it I'll dig it out. It broke about 6" behind the elbow not long after I got the bike and I put a piece of metal tubing in there to splice it.