Scooterotica

I have started to build up my TS1 motor on indian casings, I built up the bottom end to shim my gearbox and found my final drive bearing to be kinda loose fitting. There is no side to side play but it takes almost nothing to knock it back out. Once the bearing retaining plates are on it will not move. My concern is this, if it is loose fitting will gearbox oil find it's way out between the bearing and the case? Can I just use a sealant around the bearing? It's a new case and a new Casa bearing.
Thanks

CasaLambretta bearing!! I had the same thing a couple of years ago, their was a batch that were made the incorrect diameter, I remember asking the same question at the time, some suggested using bearing fit loctite around the bearing, I Chose not to take any chances and fitted an MB bearing instead.