73 T5B Kawasaki troubles

[ahersh]

Hard starting, but has good compression, 115psi with WOT. Stock Kikakki carb is pretty tired, the throttle stop plate rivet is very loose. Thinking of replacing crank seals, will call Olson Bros for parts tomorrow. Also thought of using the mikuni carb off my other 91 KC and then putting better carb on the 91??? Thoughts on that?? Yes, the old Kikakki has been cleaned out by me. I can actually get this old KC going by spraying some fuel down plug hole. Once I get it started this way, it runs, but lacks power compared to the 91.Also, when did KCs stop using points? Oh yeah, also wonder if the 91 KC (Spirit motor) recoil will work on the old Kawi motor, as it gave up on me last week. The shaft/case area cracked and I hear the case isn't available anymore separately.
Finally, would I just be better off buying a fixer up Suzuki motor off Ebay and rebuilding it for this old 73? I am a mechanic, have been forever, but new to the whole Kitty Cat thing. My boys sure like the 91, just need to get this old one going and easy starting. Thanks all.