You have a Saito 180 that does not run consistently?

#1 Recheck both valves for proper clearance.

#2 OS type "F" plug only.

#3 Reset valves to factory start points. Go to top throttle and turn lean to top rpm. Back off 300 rpm. Set idle to 2000 or so. Lean it out until it transitions well.

I just did all of that on my 72. I gained almost 1000 rpm on top, and after turning the low end needle in almost a full turn from the starting point, it whips the 14x4 to rpm quite well. After it is set, don't bug it again.