8Fun motor problems...HELP!!!

IanA

Pedelecer
Jun 5, 2011
39
5
Hi,
I've had a problem with my front 8Fun motor for a few weeks. It started with a scrape noise once per wheel revoltion when going round corners and I ignored it - I thought it would be the disc brakes that would need to be trued. But it became very loud and almost constant scraping towards the end of my last ride a week ago. Since then I've been tearing my hair out trying to get to the bottom of it.

The noise can't be heard except when riding the bike. When I looked into it I found that the wheel had a small amount of play in it (side to side) and when I took the wheel off I found that the 8Fun hub motor cover plate (the screw on version) was very loose and was only being held in place by the grub screw (whose thread was partly stripped).

To cut a long story short I've removed the brake disc from the hub to eliminate that and I've replaced both bearings in the motor.

I've just tested it after replacing the bearings and it's much improved. But there is still a sound when going round corners and it doesn't even sound like a quieter version of the original fault - more like it's a different sound altogether - and very much quieter - but it's still there!

Up to this point (2 years old and 2,400 miles since new) I've had no problem with the motor which has always been as quiet as can be expected.

I'm presuming I now need to replace the gears and clutch but as far as I know they will have to come from China and will take some time.

So my questions are...
1. Do you have any alternative ideas as to the cause?
2. If not, where's the best place to buy replacement clutch and gears?
2. Do you think I can ride the bike whilst waiting for parts without doing any damage?

I thought you might like to see my new cover plate removal tool :eek:

RIMG0355-small.jpg

It took ages to make with a knackered hacksaw blade, a B&D Wizard and a file but it works exceptionally well...

RIMG0352-small.jpg

That should fit nicely in my pannier toolkit!

Any suggestions, observations and recomendations would be very welcome.

Thanks,

Ian
 
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Alan Quay

Esteemed Pedelecer
Dec 4, 2012
2,351
1,076
Devon
Personally, I would just replace the entire thing, especially with that many miles on it. BMS battery have complete kits (without battery) for about £100 plus shipping + tax.
 

IanA

Pedelecer
Jun 5, 2011
39
5
Thanks Mike, I looked into that and shipping is over £50.
So with tax it's over £180 and that means I'm going to try everything I can before replacing it!!
 

rpurchon

Pedelecer
Sep 22, 2012
55
0
just order the motor and fit the new moving bits into your motor outer shell/wheel.if that makes sense.
to open mine i undid the grub screw and unscrewed the cover with a piece of hard wood in the notches and a hammer.
richard
 

IanA

Pedelecer
Jun 5, 2011
39
5
just order the motor and fit the new moving bits into your motor outer shell/wheel.if that makes sense.
to open mine i undid the grub screw and unscrewed the cover with a piece of hard wood in the notches and a hammer.
richard

Genius idea Richard - hadn't thought of that. Unfortunatley it's £74 for the motor on it's own compared to £100 for the whole kit (less battery) so doesn't save much :-(
 
D

Deleted member 4366

Guest
I've seen side to side-play on one of these motors before. Any play will result in your disk rubbing, which is a prime candidate for your problem. It's easy to test: Just remove the caliper and test it to see if the noise is still there. You'll still have a back brake, but obviously you need to be careful. If it is side-play, you'll have to put a shim behind a bearing or on the axle, which will be no problem for a man that can make a side-plate removal tool out of a frying pan.

Which way did the cover come off - clockwise or anti-clockwise?
 
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IanA

Pedelecer
Jun 5, 2011
39
5
I've seen side to side-play on one of these motors before. Any play will result in your disk rubbing, which is a prime candidate for your problem. It's easy to test: Just remove the caliper and test it to see if the noise is still there. You'll still have a back brake, but obviously you need to be careful. If it is side-play, you'll have to put a shim behind a bearing or on the axle, which will be no problem for a man that can make a side-plate removal tool out of a frying pan.

Which way did the cover come off - clockwise or anti-clockwise?
Thanks for that d8veh - I tried it without the calliper a few days ago but reassembled after replacing the bearings. Since it was still making a noise I decided to remove the disc completely and leave it like that until I've got it sorted. So noise is still there even without the disc. [I had also thought the screws from the disc may have caused the scraping noise as they protrude on the inside of the casing - but seems that's not the case!]
 

IanA

Pedelecer
Jun 5, 2011
39
5

IanA

Pedelecer
Jun 5, 2011
39
5
Which way did the cover come off - clockwise or anti-clockwise?
Forgot to say, it was anticlockwise to unscrew it - which threw me as I was following a YouTube video that said they were unusual in that they were clockwise to unscrew.
 
D

Deleted member 4366

Guest
You need to find the cause of the problem before replacing parts. Does it make noise going round corners both ways or just one direction? If one direction, which?
 

shemozzle999

Esteemed Pedelecer
Sep 28, 2009
2,826
686
A couple of days ago I found www.greenbikekit.com/index.php/electric-motor/bafang-bldc-hub-motor-clutch-replacement.html but it's now disappeared!!
The picture from it was...
View attachment 6047
It said it was for "Bafang bldc hub motors clutch/gear wheel for 8fun engines, SWXK, SWXH, BPM, SWXK5 etc" and it was only $25.00.
I shall have to contact them to see if it's only temporarily out of stock.
Alternative source:

easy broken parts - Shop Cheap easy broken parts from China easy broken parts Suppliers at MW motor on Aliexpress.com
 

IanA

Pedelecer
Jun 5, 2011
39
5
You need to find the cause of the problem before replacing parts. Does it make noise going round corners both ways or just one direction? If one direction, which?
Totally agree, but I've really struggled to get anywhere with diagnosing the problem and I've almost got to the point of desperation! I found that the larger bearing was rough when spun off the bike, so decided it wouldn't do any harm to replace it and might move things on, and it did. The noise was reduced. And because those bearings had worn and there was improvement by replacing it, for the sake of a few quid I decided to replace the smaller bearing. This bearing appeared to spin smoothly but replacing it had the most effect on the noise to the point where it is much quieter.

In answer to your question, the noise occurs going round corners in both directions.

I've had loads of theories about this over the last week but I'm leaning towards the idea that the cover came loose which put stress on the bearings and the gears and may have damaged them.

I also performed another test by placing a washer INSIDE the casing so that the clutch would be an extra 2mm away from the end of the casing and it had no effect whatsoever on the noise so that discounted the idea that the clutch was scraping the inside of the casing.
 

IanA

Pedelecer
Jun 5, 2011
39
5
There is another bearing in the centre of the motor which if worn could allow contact and cause the noise, found these photos on the German pedelecs site, hope this may help. John
Motor 8FUN SWXB Öffnen in der Nähe von Wuppertal
http://www.pedelecforum.de/forum/attachment.php?attachmentid=27795&d=1362858347
Wow - That's nasty!!

Had heard rumors of an internal bearing but had never understood where it might be, so thanks for that. I will translate and read through the whole article later. It looks very useful indeed - can't believe that one had been working or that they managed to resurrect it after getting into such a state. Very impressive! And that gives me lots of hope for mine, so thanks.

If my motor looked anything like the one in the picture I'd be totally understanding that it needed an overhaul - or complete replacement! But mine is pristine inside, so it's all very hard to accept.

Cheers,

Ian
 
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Boater Phil

Finding my (electric) wheels
May 28, 2016
8
0
60
Oxford
The bearings on my 8fun SWXK front hub motor are failing - does anybody know where I can get replacements? Or what sizes I need to order if they are just common or widely available bearings?
I have just replaced the worn out wheel rim so want to keep it running for another couple of years if possible.
I live in the UK.
Any advice would be welcome, thank you.
 

patpatbut

Esteemed Pedelecer
Apr 25, 2012
860
79
Ask Andy from Woosh and he might have some for you

Or order it from BMSbattery or GBK via China