Repair the BPM2

[cwah]

Hello guys,

I think I smoked my BPM2. Actually I think the clutch broke because I applied too much torque to it.

How do I open this motor?

Thanks

 

[Russell]

GBK sells replacement clutch assemblies:

http://www.greenbikekit.com/bafang-bldc-hub-motor-clutches.html

and is the only vendor I know of that also sells a tool to open the motor:

http://www.greenbikekit.com/bafang-8fun-bldc-hub-motor-opening-wrench.html

-R

 

[cwah]

I already purchased the spare clutch from bmsbattery.

Is there any way I can open the motor without having to order specifically this opening tool from gbk?

 

[Russell]

Well you could try to make something yourself or perhaps find something that might work from an automotive store.

Are you sure it's the clutch that failed? I've never had a clutch fail though I have had hall sensors fail on 3 motors.

-R

 

[cwah]

Maybe I can drill some holes to open it?

I don't know what to look for in an automotive store.

I ran the motor for 3 months at 80V 35A. After 3 months, i had strange noise when running and it went worse. Now it sounds like a locomotive so I decided to stop using it.

 

[Russell]

Yeah, well at that power level you sure were asking for a failure

I would not start drilling it but do check the function of the hall sensors before you do anything drastic .

-R

 

[cwah]

Yes, I need to find a solution :/

 

[Russell]

As I said above:

Order the tool to open the BPM II from GBK

If the problem isn't the clutch it could be the hall sensors...or you actually melted the windings. Either way you have to open it. Although if it's a hall sensor you could just buy a sensorless controller.

-R

 

[d8veh]

I've had a few side-plates come unscrewed when removing the free-wheel, which was very tight on its thread, so you could try supergluing the free-wheel on. Then you can use the free-wheel removal tool to unscrew the plate with the free-wheel. If ever you have to replace the free-wheel, you can heat it up to break the glue. Give plenty of time for the glue to go hard. Check that there's no grub-screw in the outer edge.

If that doesn't work, you have to buy or make the special tool.

 

[spinningmagnets]

I would try making the tool first. You could make it out of a beam of wood (2 X 4?), and you run two bolts through it with a hole between the bolts for the axle to fit through. Use a file to cut the tips of the bolts to make them square so they will fit into two of the slots in the face of the sideplate.

Look at the pics of Johns disassembly of the Bafang SWXH for some ideas.
http://endless-sphere.com/forums/viewtopic.php?f=6&t=47139&p=732717#p732717

Your hub has four square slots, some have three round dimples:

 

[cwah]

Thanks for both your suggestion. It looks like I need some grinding to be able to make it work. But I don't really have these tool at home and maybe buying the tool would be a safer option. Rather than trying to make a tool that may not work