Hi, I have just replaced the main shaft on my blade 450. On the top bearing there is a spacer - the replacement has 2 spacers so am I missing something or is the second one a spare.
Just happen to have looked, yesterday, at getting a spare for my Blade 450 and somewhere in the package description they mention that these are shims. If I remember correctly they said you shim it to minimize the axial play.
If it's anything like the Align "Pro" series helicopters, there is no collet on the main shaft that can slide to take up the play in the main shaft. those shims are there to do just that as stated above. Make sure to post some pictures and videos of the heli in action so that we can see it.