Earl, it's a 4000 rpm limit. I've never had to keep the igniter on after the first minute, but have almost drowned from the fuel coming out the exhaust. You are right about needing to break them in per the manual.
OF, the first Z9 was a beautiful machine as was the Mach 3. I owned a '69 250 Samurai with the last teardrop tank. Never saw a Mach 4. What I would like is a Z1 if one were to be found. You got me on the kick start in the pic as I never saw it. The engine had been modified for a left handed shifter with knob when I remember first seeing it.