I worked off a 72" wheel base as it worked well on the chapman frame. Rail material is 1" x .090 DOM tubing. The neck was machined from 1020 CRS round stock. It is set up for stock ZX7 bearings which match the donor bike components. I used a JD Squared 32 tubing bender. Some years back I made an exhaust system for the 55 Chevy and I bent up EMT conduit for patterns. It worked well then so I did that again. The pictures that I got from Oz helped a lot. The differences in Honda and Kawasaki engines created some design challenges but nothing too tough. I cut the tubing and fit it together then tack it in place with a mig. I need to get my son over to tig it. He is a much better welder than I am. Funny, I taught him to weld.
Joe