Help please, my bbs02 750 is stuck in my frame

pgcarter

pgcarter

1 mW
Joined
Aug 10, 2014
Messages
11
Location
Toronto, on. Can.
My bike was recently stripped down to frame and motor. So i bought a new bike, but i've taken off the pedals and everything and the motor just seems frozen in the bottom bracket. I've tried wd-40 and mild hammering, but it won't budge. my frame is aluminum and i'm willing to sacrifice it to get the motor off. Anyone have any suggestions?
 
I'm a little worried about getting the motor too hot, though I think maybe i might have to risk it, I don't know how to get it cold though, it's all the up to freezing here in toronto. :D
 
A picture might help us see what you are up against. I'm interested because several of my BBS02's are installed on aluminum frame bike/trikes. The first one was installed 4 years ago and removed with no problem after 1 year and replaced with another BBS02. On that bike there was a ridge inside the bottom bracket center that had to be filed down before installation. I also had no trouble removing one from an aluminum trike after two years and 2,300 miles.

Can you rotate the BBS02 at all? If the aluminum and steel have bonded there could be a problem freeing them up.

My next suggestion would be to cobble together a "puller" where a plate of some sort is solidly attached to the bike frame and a fine thread bolt can be turned against the left side of the crank axle, with protection not to damage the crank axle.

Please let us know what finally works.
 
Well, i've got a propane torch and a rubber mallet, i've been at it awhile and it still hasn't budged. Still trying but i'm at loss. the torch doesn't even bubble or discolour the paint, that's a surprise. :cry:
 
This just isn't working. Maybe the propane torch isn't hot enough, but it is what i have. I think I might have to cut the bottom bracket right out of the frame leaving some on for leverage. Cut a slot across the width of bb, using a drill and dremel, and possibly an angle grinder, and pull it apart using the parts left on for leverage. Clearly drastic action, and i would have to borrow my friend's angle grinder. It will be 4 or 5 days b4 i get the new bike so i don't have to decide right now. Another option is to take it to bike shop where i bought the new donor bike and see if they can do anything. They might tell me "they don't work on electric bikes", but....
 
hi well done use a drill bit to get the rest done. 8) from your cut .. retry take it out.

dose not work. lever the cut open. dose not work then.
try heat up again then put oil in it.

last cut out whole bb from frame
best of luck
 
leave a plastic bag with ice around the shaft area for about 10 min than get back to the hammering
 
Looks like it's had a lot of moisture getting in there and resulting rust? Squirt bottle of Liquid Wrench, spray liberally, let soak, repeat might eventually do the trick now that you've opened up a path for it to get in.
 
If soaking in lw or wd40 does not work on its own maybe you can somehow get a a gear puller to push the shaft through? Good luck!
 
That looks like the rust might have 'bonded' the parts together.
If it has then the only option may be some more cuts and 'peeling' the BB away.
Since you now have the BB split, I would try the torch again and hope heat applied to the frame would cause uneven expansion to break the bond.
 
Looks like rust in the pic, but it's just dirt, oil and spent cut off wheel. There hasn't been any sign off oxidation throughout. Aluminum and. i assume, stainless steel. I have taken it on and off a couple of times before and didn't see any corrosion. I say this because i don't want ppl to get the wrong idea about the bafang. Except for this possibly preventable problem, this motor has been trouble free for about 4 years and 7000 miles.
 
This may be a stupid suggestion but what about getting a small piece of pipe or pvc that will fit over the square drive but just inside the bb, then put an old cast iron brake drum or something similar over the other side (so the frame will allow the motor to slide out) and then press it out in a large vice or between 2 concrete walls/curbs with a car jack. You probably only need to move it 1/4" and then it may slide out easier once you break the bond.

Another possibility (and risky!) would be to put the pipe over the square drive and then put the bike on it's side on concrete and jump on the frame :)
 
Okay guys, here's the update. I had to finish the cut across the bb and then still had to cut the frame in half. Then i was able to twist the motor out. There was some rust but not that much. The motor shaft might not be stainless, maybe just anodized. I think the bb must have taken a hit, there was some vandalism done to it last year. Anyway, the motor is out, and still working. When i cut the slot i went a little to deep and cut into the motor a little, don't think it's deep enough to be a problem but I'm going to patch it up with a little jb weld. So thanks for the input guys, till next time, ride safe and have fun. :D
 
Lol - JB Weld, I use that on everything :) Thank you for your post. The next time I take my motor out I am going to grease up the shaft and the bb before I put it back together.
 
Hello mate did you manage to sort your bike i have the same problem my bafang motor is stuck on the bike frame it will not come off
 
I had the same problem with a BBSHD in a Marin steel frame.
Tried WD40 then heat and it didnt budge so I used a 14lb sledgehammer and it came out in less than a minute.
Then I bought a new motor :D .
The frame is fine and now has a BBS02 fitted with a well greased BB and hopefully wont need to be removed again any time soon.
 
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