BSA B31 Restoration Part 3 Crank - Big End & Main Bearings 

Also put the mains on before putting the crankshaft back together so that the act of pressing the main bearings on doesn't knock the run-out out of true....setting the run-out becomes the last task on the crankshaft before fitting.

As far as I can remember I got it off eBay, a Hepolite one. I do know Feked.com also sell them.

Yes the tolerance is very small and is difficult to fit, you could try putting the con rod in the freezer for 24-48 hours. Failing that you may need to take the crank & con rod to an engineering firm to have the outer race ground to fit. The I/D of the outer race gets compressed when installed in the con rod.

@@InTheShedUK Surely you would warm the conrod?- holes get bigger when heated, smaller when cooled.

@@johncrowley5612 True, like fitting bearing into a casing, heat the casing, freeze the bearing... weird as heat causes expansion in all directions, so why does this work? I've just read a Timken tech tips that said 'For a press fit, cool OR heat tapered roller bearings to aid in assembly or removal' Physics master required to explain!

Sort of depends on the grease, not all grease is equal... engine assembly grease is still a grease. It's the thickener that doesn't dissolve (just melts with heat), grease can be anything from 70-97% oil & 3-30% thickener.. Vaseline is pure hydrocarbon so it should dissolve in theory, might try mixing some with oil to see what happens. I did manage to do it without anything in the end, just took a while.