Hi guys, old man's attempt at getting fit!

[Bitsnpcs]

With the chain on the smallest rear cog I would expect the pulley cage to be in a vertical position as a way of checking for correct chain length.

Here is a pic of the bike on smallest gear, looks ok to me

Anyway I have another issue that I am hoping some here can help with

The pedal arm on the left side keeps loosening, I have tightened the nut as much as I would like to without going overboard and it just keeps coming undone

Any ideas what is wrong or what can be done to fix it?

 

[Nealh]

Chain length looks ok, to be sure remove chain from derailleur and put it (the chain) on the two largest gears the ends should meet then allow +1 more link.

For you crank remove and check both threads are they damaged or dirty, if undamaged try cleaning both threads and finally use some isoproponol then try a bit of thread glue.

 

[Deleted member 4366]

Take the crank off, degrease the square taper and the inside of the arm, then reassemble.

If you rode it much when it was loose, you might have damaged the taper in the crank arm. In that case you need to heat it right up to nearly red hot. When you then reassemble, the aluminium will reform to the correct shape, though you might have some heat damage if it's painted or lacquered.

 

[tommie]

Here is a pic of the bike on smallest gear, looks ok to me

Anyway I have another issue that I am hoping some here can help with

The pedal arm on the left side keeps loosening, I have tightened the nut as much as I would like to without going overboard and it just keeps coming undone

Any ideas what is wrong or what can be done to fix it?

Typical of the Bafang BBS left side crank arm, use a long allen key and stand on it! Red Loctite will also help

 

[Danidl]

Typical of the Bafang BBS left side crank arm, use a long allen key and stand on it! Red Loctite will also help

I once had that problem and my solution was araladite Epoxy resin. .mix and. apply the glue,onto the shaft and pedal crank screw the parts together and leave until set. I can state the fix lasts 30 years. When i needed to break the seal, i used a flame..

 

[DouglasXK]

D8veh’s solution must work. Unfortunately once allowed to loosen the taper will deform. If I were you I’d try kitchen foil first and push the crank onto a single layer of it. I had read of this problem and for the first couple of weeks i battered mine on which, touch wood, hasn’t failed.

 

[Paul chef]

There are some quite good kits on Aliexpress and there's some bad ones too. Some of them are good and cheap. If you're thinking about any one in particular, post the details here and we can tell you the good and bad points.

Just wondering if I could get your opinions on this kit?

https://www.aliexpress.com/store/product/Free-Shipping-BBS02-Bafang-8fun-48V-750W-Mid-Drive-Electric-Motor-Kits-Configuration-48V-17Ah-Li/1473151_32828017684.html?spm=2114.12010612.0.0.69bc172dQx96tV

 

[anotherkiwi]

Ask what cells the battery uses. With the 750 W motor you want 15A or even better 20A brand name cells.

 

[Deleted member 4366]

Just wondering if I could get your opinions on this kit?

https://www.aliexpress.com/store/product/Free-Shipping-BBS02-Bafang-8fun-48V-750W-Mid-Drive-Electric-Motor-Kits-Configuration-48V-17Ah-Li/1473151_32828017684.html?spm=2114.12010612.0.0.69bc172dQx96tV

Check where your bottle fixings are. Those batteries have theirs in the top end,mso in most cases you need to drill your frame and insert your own rivnuts.