The ATF trick is one I DONT RECOMMEND. You got about a 50/50 chance of either making the motor better, or ruining it. Why? Because if you knock a big enough chunk of carbon off in the process, you will carbon lock your motor. Also, the ATF trick is a last ditch effort to safe an ailing motor. Its not a procedure that neesds to be repeated. I will not pour ATF in any rotary, instead, I use MMO, or will do water injection.
ALSO, everyone here should know that white smoke on startup is a sign of a worn motor that is on its way OUT. DO NOT BUY THAT MOTOR!
Jarrett