Italian Rossi 40 motor

Rossi 40 motor made by CELLATICA-Brescia Italy had been obtained last year, but it was thrown away because of malfunction of throttle valve, stuck feeling while hi-lo barrel movement. Careful checking has proved that the problem was caused by abnormal cutting of oblique guiding groove for fuel squeezing mechanism, step difference and surface roughness, also a tension spring for out side pushing effect keeping the squeezing fuel constant was too strong.
Diamond filing and polishing the surface touching the guiding pin head made the movement so smooth as desired.
Tension spring was replaced into that with lower spring constant, it should meet with the requirement for primary compression pressure vibration .

Though 435 gr weight is not so light as HP 40 mentioned before, disassembling procedure revealed that Rossi 40 motor is well designed, machined and finished as if it is some marvelous craft, assembling tolerance of all moving parts are adequate, especially ABC piston & cylinder construction is excellent as to make me feel to use actually and to last me so long.
As for the muffler setting, the pitch value is the same as OS 40 FSR or ENYA 40X , not so specific modification is necessary.
Not a few 40 class motors have I to be tested not on test bench but on the airplane in actualy functional situation.

Hornet was lost that had been intended to be used as a actual flying motor test bench, how come.
Inviting Kyosho ARF model Calmart 40 is one of my choice, but a painted & finished Explorer 40 is hanging from the ceiling----?
How would be my decision?