As much as I always loved the KZ650, no good for touring. I did two trips, 1980 2000 miles, 1981 3200 miles. Keep the 650 for around town, small trips ect. Don't expect much reliability, fun or comfort on a long trip. For that get a KZ1000, KZ1100 or the like. I know these are not lightweights, but adding the weight even if 100lb you will never regret if touring.
I am currently building a KZ650 with a KZ1000 transplanted into it, MTC 1197 to be exact.
I believe this will be the best of both worlds, lighter weight, handling, smaller overall. The heavy KZ1000 crank generates a lot of torque, much more than the smaller motor even built up can generate.
Bought some VM33 carbs, had the crank welded, just need to get the top case cleared for the bigger liners.
Just had a Z1 head ported/big valved and it flows over 95 CFM.
Body work and running gear will be stock 650.