Originally Posted by
FlyerInOKC
The
run the engine for 10 minutes at each each rpm, 4k, 5k, 6k and 7k sounds like the procedure Super Tigre specified for their 2 cycle ringed engines and it works too.
The Hirtenberger HP21VT is a nice looking engine but when I buy another engine I think I'll go with a Saito in the 100 to 120ish size. Didn't want to upset Pete by typing a "5" on the end. 
You know how sensitive he his.
Angry yes, i hate dem fa125's but your statement does not rule out buying an fa115...sensitive? hell no, i'd need an IQ higher than your average two stroke heli pilot to feel that. When you spend money on a brand new engine like the fa120r3 it's normal to get a bit anxious and over think it running them in, at least i do. Good advice from lonnie re tuning. I never bother with valve lash until it's run in and ignore, in fact put your temp gauge away, having a single carb feeding multiple cylinders you are always going to have to compromise on mixture, just tune it like you would any saito single. Top rpm is good you won't go anywhere near seizing it unless it's an fa125 with one of those gawd awful graupner props on it
ps if it drops a lower cylinder during the initial run in don't assume it's bad plug, my fa200r3 had a pushrod slip off a rocker cup before it was properly seated, yes there is room inside the rocker cover for this to happen with no damage. Personally i was so relieved i had a beer or 15.