How to change ID number of the BSx4s Series

2021.10.8 How to choice and Settings, Other Servos topic


I am sorry that it has been a while since I have updated this page.

I'll be updating more frequently, so please stay tuned!

The BSx4S-Grasper STD went on sale this week, and I'm sure it has been shipped smoothly and has arrived at your doorstep.

We've been getting a lot of questions about how to connect the BSx4S-Grasper to the KR-420XT's B/S port, and how to move the throttle servo. How do I connect to the KR-420XT B/S port and move the throttle servo?

The servos of BSx4S series can be set to [ID]. ID:1 works as a steering servo and ID:2 works as a throttle servo.

The factory default setting is ID:1, so it operates as a steering servo.

If you want to use it as a throttle servo, you will need to change it to ID:2, and we will show you how to change it.


Products required

■EX-NEXT LCDエXpansion Unit2 EXP-201

Serial Branch adapter or Servo Twin Extension Wire II w/new plug

■Products commercially available as batteries for radio and receiver (LiPo 2S/LiFe 2S/Nickad/Nickel metal hydride)


1 Change ID with EX-NEXT Expansion Unit

Remove the rubber cap of the Expansion and connect the following in this order: (1) Serial branch adapter (2) Throttle servo (3) Battery to turn on the Expansion and display the setting screen. (Please note the polarity of the connector.

*For the purpose of photography, the expansion unit is removed in EX-NEXT, but you can leave it installed.


Move the cursor to SERIAL SERVOMOTOR SET and press the ENT button.


The factory default is ID:1, so change it to ID:2.

This completes the servo setting changes.


2 Installing the servo in the chassis

Since they are the same servo, mount the steering wheel and throttle without mistaking them. It might be a good idea to mark them with masking tape.

Use the Serial branch adapter to connect the steering and throttle servos to the KR-420XT's B/S port.

The receiver battery can be connected to any available channel 1 to 4.



3 Let's check the ICS settings with EX-NEXT's telemetry function.

Turn on the power to the radio and receiver.

"Turn on the power to the radio and receiver, and go to FUNCTION > TLMY > RELICS.

First, READ ID:1 will be read, and the steering servo setting values will be displayed.

You can change the values here to set the steering servo.


When setting the throttle servo, READ ID: 2 will display the throttle servo setting values.

By changing the value here, the throttle servo can be set.

*If "RELICS" is not displayed on the expansion unit, change the RF mode to "TLMY" because it is set to "ADV" or "MX-F".

*If the setting value is marked with ***, communication with the receiver is not possible. Please check if the receiver is turned on and paired properly.


4 Speed adjustment of BSx4S-Grasper STD

The speed of the BSx4S-Grasper STD is 0.09sec/60° at 7.4V, so it is the best match for 1/10 electric off-road and 1/8 engine racing steering.

So, what about for throttle? It has a torque of 40.0Kg-cm (7.4V), which is more than enough for a throttle servo. However, the speed is too fast, so let's try to reduce the operation speed by using the "SPEED" function of the radio.

We recommend setting the throttle speed to about 70% to get a natural feeling.

Also, in categories that do not require fast steering speed, such as 1/8 GT cars, setting the steering speed to 70-80% will make the car extremely easy to control. Please try it.


●Lowering the servo's "SPEED" will also lower the torque, so leave the value as it is. Use the radio's "SPEED" to adjust!


If you have any questions on how to set this up, please feel free to contact the Kondo Kagaku Service Department at or ℡03-3807-7648!

Thank you again for reading this article.

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