I am replacing the main ballrace in my gearbox on my 1944 bsa m20. However, I can't seem to remove the top gear from the shaft that is mated with the bearing. Any suggestions please?
Once the mainshaft has been removed its just a case of tapping it out (into the box) using a wood drift or similar once the sprocket retaining nut & sprocket are off the outside.
I think Jeff' problem is that the bearing has come out of the box attached to the sleeve gear.
Cut the bearing off with an angle grinder or try to insert some wedges behind the bearing but this method will destroy the shim behind the bearing
oops let me clarify. The main shaft, top gear, and main bearing fell out of the gearbox as soon as i removed the sporcket and nut, but the three are still attched together. Now do you just slowly pry them apart so eventually the bearing falls off of the main shaft? Does the bearing have to be taken off a certain direction such as toward the sprocket or towards the top gear? Thanks gain for the help
The shaft should be a sliding fit in the gear but if it's seized knock the main shaft towards the gear lever side tben the bearing has to be removed towards the sprocket.
This could mean that your new bearing could be too loose a fit in the case. Usually you have to heat the case to put the bearing in. If your bearing goes in too easily, a smear of Loctite bearing fit will probably save the day. It might be that something has seized and caused the bearing to spin in the case.
You could try clamping your old bearing in a vice and knock the sleeve gear out. Ron.
Oh i see, I've not had that happen on an M box. but yes its just a few minutes with a grinderette cutting wheel, i do that on modern Ford transit front wheel bearings, when you get to the inner race only grind until its thin & goes blue rather than right through it.
