RE: Saito shuts off
You say its running rich. Are you seeing smoke from the muffler?
Most saitos will run and stay running by turning the high speed needle all the way in, then back it back out 3 1/2 turns.
At 10300 rpms.....your actually running a little high and sounds like you may actually have the motor too lean. This will definitely cause a motor to shutdown after a minute or so.
Most saitos ive got are running their best at 9000-9500 on the ground....some even slightly lower like 8500(the bigger ones).
This motor is new or used? If its used...did you set or check the tolerences/gap setting with the tools?