Ibelieve my TT 91 FS is an early one, it required a carb change to settle down and run right, it was binding really bad and was taken care of under warranty. Ihope to mount it up and really test it some day .
My Magnum 52 RFS took about a gallon of flying to settle down and behave. However my first Mag 52 RFS had to be completely replaced under warranty.
My Saito 52 was easy peezy right from the start and got even better after the first gallon.