Bafang SWXH Repair Opening One Up

zukster

zukster

1 kW
Joined
Sep 11, 2008
Messages
403
Location
North Vancouver, BC, Canada
Has anyone opened one of these up? It doesn't have screws like the black one.

The screws at the top are just for the disk brake.

motor-in-vice-small.jpg
 
There are three dents in the drive side. You will need to put a spanner wrench in them and screw off the cover- counterclockwise like a normal screw.
 
Hey - thanks a lot for all the help John. These are the 3 dimples I take it.
Is the spanner you used one that is for the bike world, or just a typical automotive one?

motor-spanner-dimples-small.jpg
 
Any spanner that fits snugly will do. I am sure the factory has a special one with a backing nut to hold it down.

I have had to get my 18" channel locks out on a few motors, as the spanner just didn't have enough leverage to get it open.
 
That does not exactly sound super easy. I don't even have a proper vice if you
check out the picture above. Looks like I need a freewheel puller too.

So altogether:

18" Channel lock pliers (maybe)
Bigger vice
Freewheel puller
General Purpose Spanner Wrench
 
The freewheel tool will be needed if you have the freewheel still attached. I have never used a vice to take one apart. If anything, a board with the ISO break mount pattern drilled to fasten to the housing would be more useful. Is it laced up inside a rim?

The channel locks are a hack method of taking it apart, I just grabbed the rim of the thread-on face and opened the case like a jar.
 
johnrobholmes said:
The freewheel tool will be needed if you have the freewheel still attached. I have never used a vice to take one apart. If anything, a board with the ISO break mount pattern drilled to fasten to the housing would be more useful. Is it laced up inside a rim?

The channel locks are a hack method of taking it apart, I just grabbed the rim of the thread-on face and opened the case like a jar.
Click to expand...

Yah - its still laced in the rim. I want to swap the guts out of a new motor because the one in the rim is baked. Otherwise I
have to get the shop to unlace the old and lace the new motor.

The board attaching to the disk brake holes sounds like a good idea if needed. So you were able to use the Spanner Wrench and
take some of them off by hand? Then you resorted to the 18" channel locks and the jar method for the tough ones?

I think I'm going to give this a try - and just get the Spanner Wrench and Freewheel Puller to start with. The other problem with
the local shop is that they're booked up for a week before I could get them to do anything. I take some pics of taking
it apart.
 
not fair, you gotta unlace that rim and put the new motor in. i am doing that right now, swapping a bad rim for a good rim on my 9 continents motor and it is almost twice the diameter of the little bafang.

no way you get outa that. sounds like a guvment job, plus you never know what bad things can happen when you pull the motor.

but i would like to see how baked.
 
:mrgreen: I'm still looking for tools.

Looks like spanners will be tough to do. You'd need a kit with different spanners and pins
handy for this to be practical. These face spanners come in adjustable ones too.

For the Bafang you would need a metric spanner that is 4cm C-C (that's how they say pin
center to pin center) and a pin hole of 8mm, for which there is a 7.8mm pin for. I saw some
adjustable ones on-line as above online, but I don't think I'll find them around town.

So I'm thinking that the 18 inch channel locks are the way to go. The Channellock(tm) ones
look pretty nice but the ones that work are the 480 BigAZZ and the 483 V Jaw 20 inch ones
which are $$$. So I'm looking for the mentioned 18 inch ones if anyone can recommend some?
 
I replied to your other thread.

Your bafang is a bit different to the 2 I have. Mine don't have any writing stamped into them like yours.

If you don't have the freewheel removal tools, you can take the wheel to a bike shop and ask them nicely to remove the freewheel (if you don't want to buy the bike tools to do it yourself).

I'd still try to swap motor cores and save yourself the trouble of a new rim and wheel build with another bafang.
 
the spanner to turn that is not a three pronged fork.

the spanner will be built like a slight hook to wrap around the freewheel threads and have just one peg sticking out the side to hook only one hole, and then you unscrew by torquing it around the freewheel hub.

those kinda spanners are actually fairly common, maybe an auto transmission shop or some machinist may have one. and you can hold the body of the hub by using a chain wrench, not channellocks.

still sucks if you get off easy, and i hadda go through this today.
 
I'll look into the the special spanner mentioned. I was not looking for that kind yesterday.

I think John used the channellocks on the cap itself. There is just enough of a lip on the
motor cap to grab it.

motor-lip-small.jpg


I think I'm going to get these because I hate being stuck. They kinda look handy to
have around as the ultimate last resort. They open up to 5 1/2 inches.

big-cl-small.jpg
 
or you can use a pipe wrench.

i have been known to open such items by using a chisel to cut into the perimeter lip and start it that way.

usually the things will unscrew by hand once you start it, and if you are trashing this case, the damage from the chisel doesn't matter, or you can file the divot off the edge.

still think it sucks that i hadda unlace my rim and relace it in a new one. you gotta suffer more for smokin that motor.
 
I'm not sure I smoked it yet. The hall sensors are not working. They're all stuck on 5V.
No heat or smell when it stopped running. Keywin said a sensorless controller would likely
get it going. So I don't want to trash any cases. I'd rather keep the hall setup because
it seems that a "statefull" controller should run better.

I tried my pipe wrench but its not big enough :( I really want those 20 Inch V Jaw
pliers now that I saw them. Sucker for tools.
 
i don't think it will trash the case. if you use a sharp enuff chisel so it doesn't bounce. i would expect it only to cut into the edge about 2mm max. nothing to really create problems, and then it should open by hand.

or you can then wrap a leather strap around the freewheel hub and cinch the strap in some vise grips and it should give you enuff leverage to unscrew it after starting it with a chisel. if it has never been torqued by running a freewheel, it may only be slightly more than finger tight, maybe chinese girl assembler torque tight.

maybe a leather strop wrench on the freewheel hub will turn it or add the two at the same time, twist with the strap and tap with the chisel.

i doubt if anyone will ever notice it, not gonna damage the real parts either to have a chisel scratch on the edge of the face plate.
 
When I hit the lip with a chisel it totally fubar'd it. The metal is so soft that the chisel just cut in and the case didn't open. i actually have a motor with perfect internals but a messed up case that I cannot get open in any way.
 
ok, scratch that, holmes knows.

go look for the spanner, the vise grips are just macho mania, i bet you can find one. the hole size is not important, just need a pin smaller than the hole and with the curved part long enuff to go around the hub freewheel boss.

still not fair. all the halls are latched at 5V? never changes? bad ground?
 
johnrobholmes said:
i actually have a motor with perfect internals but a messed up case that I cannot get open in any way.
Click to expand...

Interested in liquidating that damaged asset? Front or rear?
 
It was a rear, and upon closer inspection I bumped some wires with a drill bit and muched them. Oh well, now I have three stators ripe for rewind :roll:
 
johnrobholmes said:
There are three dents in the drive side. You will need to put a spanner wrench in them and screw off the cover- counterclockwise like a normal screw.
Click to expand...

I picked up some 20 inch channel lock pliers today. They adjust up to 5 1/2 inches. Sweet :!:
Just want to confirm that it's counter-clockwise before digging into the soft cap.

Also. More fun today with the freewheel puller I picked up.
A Fitzer Shimano compatible puller from Mountain Equipment Co-Op, or MEC.
Just to note, I'm using a SunRace MFM60 13-32 8 speed freewheel. Fit fine.

filzer-freewheel-puller.jpg


You can't see the bottom of the nut side in the pic, but there is a hole for the normal
bike axle to fit through. The Banfang is bigger, at about 1/2", so it did not fit. Off
to Home Depot again for big drill bits. Back home. Toasted the 1st bit. It was not
hard enough :cry: Back to Home depot again for Cobalt drill bits instead. They had
no problem taking the damaged bit back. They didn't even ask if something was
wrong with it :shock: If the specialist hadn't told me that the black oxide bits
should be okay, I wouldn't have even considered taking it back. Now I think I'll
just take them all back once I'm finished using them :twisted: hehehe.

Too tired to drill it tonight. Hopefully, the harder bits will work tomorrow.
 
johnrobholmes said:
It was a rear, and upon closer inspection I bumped some wires with a drill bit and muched them. Oh well, now I have three stators ripe for rewind :roll:
Click to expand...

Do you rewind them yourself or have a shop do them? How much does that cost?
 
I will rewind myself. Can't guess on cost. If it only took an hour I would charge $55 for labor and materials. Never wound one though, so I don't know how long it will take.
 
zukster said:
John, I just wanted to confirm that it's counter-clockwise to take off the Bafang motor cap?
Click to expand...

Zukster, if it is not CCW, then normal pedaling would unscrew the motor case. By inspection, it must be RH threads, normal CCW, lefty loosey, righty tighty.
 
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