Clutch rub

Hi Guys,
Having recently stripped my gearbox (li150) I took the opportunity to replace the clutch plates at the same time. I now find the the clutch inner bell is rubbing on the inside of the chaincase, causing a bit of clutch slip. Nothing is different other than the new clutch plates. Any ideas why this would happen? Or a solution? Just a thicker chaincase gasket?
Many thanks, Alex.
Having recently stripped my gearbox (li150) I took the opportunity to replace the clutch plates at the same time. I now find the the clutch inner bell is rubbing on the inside of the chaincase, causing a bit of clutch slip. Nothing is different other than the new clutch plates. Any ideas why this would happen? Or a solution? Just a thicker chaincase gasket?
Many thanks, Alex.