Bill
Manuals
http://www.horizonhobby.com/pdf/SAITO_Small-Medium_single_cylinder_Manual.pdf
http://www.horizonhobby.com/pdf/SAIControlLineAddendumLoRez.pdf

Break-in RPM 3-4k rpm. You must use a tach. Taching a 4S by ear is useless. Fuel YS 20-20. Always use synthetic only, always.
You will have difficulty keeping the RPMs low enough for break-in without an RC Carb. If you can find an RC carb it will ease break-in.
45 minutes to an hour. And yes, Saitos must be broken in, they aren't a YS.

 I checked the parts list and my 56 RC carb does not fit a 72. However, if I'm wrong, PM me and I'll send it to you for break-in.

You can choke it down by modifying the C/L carb per the expert-Bob Reeves.

Another option is to use a small piece of angle Alum cut to fit the width of the backplate. Drill thru 2 holes to match the bottom 2 screws on the backplate. Drill and tap the other side of the angle for a nylon screw like a 1/4-28 so the screw goes into the carb opening. This will choke it down and slow it up some. You probably have to start with it real close to the spray bar spigot.

If you try and run it with the stock C/L carb, open the needle to slow it down. Keep the plug lighter on to keep it running.

You don't need the lock nut unless you plan to stand in front of the plane while its running.

Good Luck

Mike

Electric starter!
Just swipe it from an RC guy when he's not looking.

Bill,

Absolutely use the lock nut!!  Four strokes are notorious for kicking back when rich.  I can't tell you how many times I saw props flying off the early series four strokes before the manufacturers got wise and started including the lock nuts.  I even had one come off at high RPM from a poorly set mid-range in the R/C carb. It flew past my ear close enough for me to hear the prop air wake.  Very scary!!  Never again!

Be safe,
Paul