diff --git a/ArduCopter/ArduCopter.pde b/ArduCopter/ArduCopter.pde
index 3a41fa1908..c0054897ea 100644
--- a/ArduCopter/ArduCopter.pde
+++ b/ArduCopter/ArduCopter.pde
@@ -2066,10 +2066,6 @@ static void tuning(){
         g.pid_throttle.kD(tuning_value);
         break;
 
-    case CH6_TOP_BOTTOM_RATIO:
-        motors.top_bottom_ratio = tuning_value;
-        break;
-
     case CH6_RELAY:
         if (g.rc_6.control_in > 525) relay.on();
         if (g.rc_6.control_in < 475) relay.off();
diff --git a/ArduCopter/Parameters.pde b/ArduCopter/Parameters.pde
index b5535a25b1..ea763b2409 100644
--- a/ArduCopter/Parameters.pde
+++ b/ArduCopter/Parameters.pde
@@ -380,7 +380,7 @@ const AP_Param::Info var_info[] PROGMEM = {
     // @DisplayName: Channel 6 Tuning
     // @Description: Controls which parameters (normally PID gains) are being tuned with transmitter's channel 6 knob
     // @User: Standard
-    // @Values: 0:CH6_NONE,1:CH6_STABILIZE_KP,2:CH6_STABILIZE_KI,3:CH6_YAW_KP,4:CH6_RATE_KP,5:CH6_RATE_KI,6:CH6_YAW_RATE_KP,7:CH6_THROTTLE_KP,8:CH6_TOP_BOTTOM_RATIO,9:CH6_RELAY,10:CH6_WP_SPEED,12:CH6_LOITER_KP,13:CH6_HELI_EXTERNAL_GYRO,14:CH6_THR_HOLD_KP,17:CH6_OPTFLOW_KP,18:CH6_OPTFLOW_KI,19:CH6_OPTFLOW_KD,21:CH6_RATE_KD,22:CH6_LOITER_RATE_KP,23:CH6_LOITER_RATE_KD,24:CH6_YAW_KI,25:CH6_ACRO_KP,26:CH6_YAW_RATE_KD,27:CH6_LOITER_KI,28:CH6_LOITER_RATE_KI,29:CH6_STABILIZE_KD,30:CH6_AHRS_YAW_KP,31:CH6_AHRS_KP,32:CH6_INAV_TC,33:CH6_THROTTLE_KI,34:CH6_THR_ACCEL_KP,35:CH6_THR_ACCEL_KI,36:CH6_THR_ACCEL_KD,38:CH6_DECLINATION,39:CH6_CIRCLE_RATE
+    // @Values: 0:CH6_NONE,1:CH6_STABILIZE_KP,2:CH6_STABILIZE_KI,3:CH6_YAW_KP,4:CH6_RATE_KP,5:CH6_RATE_KI,6:CH6_YAW_RATE_KP,7:CH6_THROTTLE_KP,9:CH6_RELAY,10:CH6_WP_SPEED,12:CH6_LOITER_KP,13:CH6_HELI_EXTERNAL_GYRO,14:CH6_THR_HOLD_KP,17:CH6_OPTFLOW_KP,18:CH6_OPTFLOW_KI,19:CH6_OPTFLOW_KD,21:CH6_RATE_KD,22:CH6_LOITER_RATE_KP,23:CH6_LOITER_RATE_KD,24:CH6_YAW_KI,25:CH6_ACRO_KP,26:CH6_YAW_RATE_KD,27:CH6_LOITER_KI,28:CH6_LOITER_RATE_KI,29:CH6_STABILIZE_KD,30:CH6_AHRS_YAW_KP,31:CH6_AHRS_KP,32:CH6_INAV_TC,33:CH6_THROTTLE_KI,34:CH6_THR_ACCEL_KP,35:CH6_THR_ACCEL_KI,36:CH6_THR_ACCEL_KD,38:CH6_DECLINATION,39:CH6_CIRCLE_RATE
     GSCALAR(radio_tuning, "TUNE",                   0),
 
     // @Param: TUNE_LOW
diff --git a/ArduCopter/defines.h b/ArduCopter/defines.h
index d11ba2acf5..0026ee6208 100644
--- a/ArduCopter/defines.h
+++ b/ArduCopter/defines.h
@@ -156,7 +156,6 @@
 #define CH6_THR_ACCEL_KP    34          // accel based throttle controller's P term
 #define CH6_THR_ACCEL_KI    35          // accel based throttle controller's I term
 #define CH6_THR_ACCEL_KD    36          // accel based throttle controller's D term
-#define CH6_TOP_BOTTOM_RATIO 8          // upper/lower motor ratio (not used)
 #define CH6_RELAY           9           // switch relay on if ch6 high, off if low
 #define CH6_WP_SPEED        10          // maximum speed to next way point (0 to 10m/s)
 #define CH6_LOITER_KP       12          // loiter distance controller's P term (position error to speed)
diff --git a/libraries/AP_Motors/AP_Motors_Class.cpp b/libraries/AP_Motors/AP_Motors_Class.cpp
index 98f7298c98..32d8c1fad3 100644
--- a/libraries/AP_Motors/AP_Motors_Class.cpp
+++ b/libraries/AP_Motors/AP_Motors_Class.cpp
@@ -14,10 +14,7 @@ extern const AP_HAL::HAL& hal;
 
 // parameters for the motor class
 const AP_Param::GroupInfo AP_Motors::var_info[] PROGMEM = {
-    // @Param: TB_RATIO
-    // @DisplayName: Top Bottom Ratio
-    // @Description: Not Used.  Will control the speed of the top motors vs bottom motors on frames such as the Octo-Quad and Y6
-    AP_GROUPINFO("TB_RATIO", 0, AP_Motors,  top_bottom_ratio, AP_MOTORS_TOP_BOTTOM_RATIO),      // not used
+    // 0 was used by TB_RATIO
 
     // @Param: TCRV_ENABLE
     // @DisplayName: Thrust Curve Enable
@@ -56,8 +53,6 @@ AP_Motors::AP_Motors( RC_Channel* rc_roll, RC_Channel* rc_pitch, RC_Channel* rc_
 
     AP_Param::setup_object_defaults(this, var_info);
 
-    top_bottom_ratio = AP_MOTORS_TOP_BOTTOM_RATIO;
-
     // initialise motor map
 #if CONFIG_HAL_BOARD == HAL_BOARD_APM1
         set_motor_to_channel_map(APM1_MOTOR_TO_CHANNEL_MAP);
diff --git a/libraries/AP_Motors/AP_Motors_Class.h b/libraries/AP_Motors/AP_Motors_Class.h
index dc4e6d4a81..db6a7da7ac 100644
--- a/libraries/AP_Motors/AP_Motors_Class.h
+++ b/libraries/AP_Motors/AP_Motors_Class.h
@@ -38,10 +38,7 @@
 #define AP_MOTORS_H_FRAME           3   // same as X frame but motors spin in opposite direction
 
 // motor update rate
-#define AP_MOTORS_SPEED_DEFAULT 490
-
-// top-bottom ratio (for Y6)
-#define AP_MOTORS_TOP_BOTTOM_RATIO      1.0
+#define AP_MOTORS_SPEED_DEFAULT     490 // default output rate to the motors
 
 #define THROTTLE_CURVE_ENABLED      1   // throttle curve disabled by default
 #define THROTTLE_CURVE_MID_THRUST   52  // throttle which produces 1/2 the maximum thrust.  expressed as a percentage of the full throttle range (i.e 0 ~ 100)
@@ -142,9 +139,6 @@ public:
     // final output values sent to the motors.  public (for now) so that they can be access for logging
     int16_t             motor_out[AP_MOTORS_MAX_NUM_MOTORS];
 
-    // power ratio of upper vs lower motors (only used by y6 and octa quad copters)
-    AP_Float            top_bottom_ratio;
-
     // var_info for holding Parameter information
     static const struct AP_Param::GroupInfo        var_info[];