Anyway, back to the point. Hi-Low, I hope you manage to fit the belt ok and get the machine working fine. Hopefully the servo motor works fine because if it doesnt, then the belt may break again prematurely.
The X4 motor belt part number should be 5463 but the older ones and the X1s will have a 5379 belt from the motor. Yours should definitely have a 5463. 
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