Hardtail is tacked on! Still gotta weld it out though.
You can read abt my opinion and others opinions as to the fit up of the Elswick tail here:
http://www.xs650.com/forum/showthread.php?t=7695&page=7
Not a perfect fit but worth it for the best looking tail out there.. IMO.
Here's how I went abt the process:
1. Basic trimming of the frame as described in previous post.
2. I tacked four short posts made of square tubing to the table around the front loop so that it couldn't spin/turn/move at all while fitting the tail. Next, I set the hardtail in place and snugged it up into the front loop. Then I pulled my tape from the headtube to centered marks I made at the rear of the axle plates (like in the pic below) to get the tail in line with the front loop. Then to hold it in place I tacked two more pieces down beside the lower rails of the tail so that it couldn't spin/turn/move. The pieces of square tubing have to be VERY tight against the frame so that it can't wiggle or move at all for them to serve their purposes. See pic below to make sense of the words above..
3. I then laid my level across the tops of the lower frame rails of the front loop to make sure it was sitting level on the table. Next, I laid the level across the tops of the axle plates to make sure my reading matched the front and that the tail was level.
4. Then I remeasured everything... like a zillion times to be sure!
5. Next I tacked everything together. I put two tacks on each joint, 180* of each other.
That's as far as I got that night. When welding the tail out be sure that you keep it in some kind of jig (in my case, the pieces of square tubing) so that it can't pull to the left or right as the welds cool. Also be sure to jump left to right, back and forth with your welds. Don't make multiple welds on the left side of the frame and then jump to the right side and make several welds, as your frame will inevitably be pulled to one side or other at the rear. Also, as most of us already know, either leave your engine in the frame or use an engine jig so that your motor mounts will line up when you go to put the engine back in.
Whew, the hard part is almost over!