This tutorial is to change a defective BBS02 motor core.
You will need the core itself , Click here.
You better don't take any chances and order a paper gasket, Click here.
Tools needed:
1) Remove the plastic secondary gear cover. (don't pay attention on this photo the controller is already removed)
Inpect the secondary gear for:
I will do a Knowledge base thread on it and will link it here or use this link to Karl's amazing blog

2) remove the 3 hex bolts that hold the controller and gently pull on it. Unplug the 3 bigger phase wire connectors (yellow, green and blue wires) and unplug the smallest black JST connector .
Next remove the silicon around the 3 phase wires using a small flat head screwdriver and the blade, pay attention not to cut the insulation on the wires.
Move on to the white recessed connector at the bottom, use a screwdriver to remove or cut the silicon around it, On the picture you see my screwdriver is pointing to a place on the connector that is a plastic lock the hold the connector in place, you have to slide a screwdriver in between the latch and the motor casing and press toward the plug to unlatch it. Gently pull on the connector while doing it.
Now you can set the controller aside.
Put back the plastic cover over the secondary gear.... just so you won't put grease everywhere!!!
3) Remove the clear silicon sleeve over the 3 phase wires and save them for later.
Flip the motor to the order side and remove the 4 hex bolts that secures the motor to the casing.

You will need the core itself , Click here.
You better don't take any chances and order a paper gasket, Click here.
Tools needed:
- You will need a small blade or razor
- Set of Allen keys (Hex)
- Philips head screwdriver
- Flat head screwdriver
- Silicone
- Possibly some white lithium grease (stuff used by Bafang : Unical Aviation Synthetic Grease AG-11)
1) Remove the plastic secondary gear cover. (don't pay attention on this photo the controller is already removed)
Inpect the secondary gear for:
- Lack of grease (black moly grease)
- Dirt mixed in the grease
- Creamy grey consistency (water mixed to it)
I will do a Knowledge base thread on it and will link it here or use this link to Karl's amazing blog
2) remove the 3 hex bolts that hold the controller and gently pull on it. Unplug the 3 bigger phase wire connectors (yellow, green and blue wires) and unplug the smallest black JST connector .
Next remove the silicon around the 3 phase wires using a small flat head screwdriver and the blade, pay attention not to cut the insulation on the wires.
Move on to the white recessed connector at the bottom, use a screwdriver to remove or cut the silicon around it, On the picture you see my screwdriver is pointing to a place on the connector that is a plastic lock the hold the connector in place, you have to slide a screwdriver in between the latch and the motor casing and press toward the plug to unlatch it. Gently pull on the connector while doing it.
Now you can set the controller aside.
Put back the plastic cover over the secondary gear.... just so you won't put grease everywhere!!!
3) Remove the clear silicon sleeve over the 3 phase wires and save them for later.
Flip the motor to the order side and remove the 4 hex bolts that secures the motor to the casing.
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