I just found a ton of power in my 72. I opened up the the baffles in the muffler one drill size at a time untill I got to 5/32. That alone was good for 500 rpm and the rich mid-range went away and it ran perfect from idle to WOT. I also picked up some Cool Power 30% heli mix and that was good for a few hundred more rpm and a great low idle. I've heard guys talking about the Saitos on 30% are much happier engines and mine seems to be.