I know this. As far as the one-way, the engine has to idle, and looking at it it turns clockwise, without engaging the oneway so, you should be able to turn the shaft counter-clockwise and it should turn free. It should lock turning clockwise. As for the bell, this is the only photo I can find of a new one and it doesn't have any groves. Taking out the grooves increases the distance the shoes have to expand to make contact so higher RPMs and..the bell will become weaker as the material become thinner and could crack...and knowing Chinese minimal standards as they are...it most likely will come apart under load. Just my opinion but I think you need to replace the shaft and both shaft bearings if you haven't already. Sounds like one is bad and if it is, the other is probably near it's limits. The one in the cover is a MF'r to get out but heat is your friend...and re-pack the new one before going back in. They don't put much in them in China.