I am completing the rebuild of a BBS01 electric bike mid-drive motor from Bafung. Would like to lubricate and protect every part properly before reassembly. Should I lubricate the clutch and if so with what lubricant? I have read concerns about slippage in a lubricated clutch. Thanks in advance!
Not sure I'd call that a clutch.... ;) More a freewheel.
On the one I had, however, it had a seal which meant there was no way the grease could get out. Something important to note is that, if you DO have one of these with a seal on them, don't competely fill it with grease. Where you have moving parts, you want a void and a way for it to 'breathe', otherwise the seal will physically pop. You want more air than grease; Air is compressible, grease (classed as a liquid) is not.
If it's not sealed, only a very thin layer. It's purpose is to keep it lubricated and to keep the teeth themselves clean and not directly contacting metal-on-metal, a bad thing in an electric motor which moves very fast under heavy load. If you use too little, the gears will chew each other up, making what little grease there is turn into a grinding paste. Too much grease, and it'll start blurting out of the side, onto other vital, expensive components.
That's not a clutch. It's the same type of freewheel that's in most hubs. There is plenty of info available online about servicing them. I found this guide on Park's web site, which recommends grease. There's a link the stuff they make but there are many that will work just fine. http://www.parktool.com/blog/repair-help/freehub-service