Hitchcocks Forum

Hi I am replacing the mains bearing in the crank case on the drive shaft of a twin is there an advantage or disadvantage in using the sealed type bearing. If leaving the seals on will it result in lack of lubrication ? if so I thought I would remove the inner seal and leave the outer side on which would stop any oil leaking or blowing out into the chaincase which I dont think happens any way? and perhaps stops any ingress of dirt.or is it best to remove both seals so that air can pass through as I heard that sealed bearings may run hotter depending where they are used appreciate any information

I would remove both seals myself for the reasons you have written

Early Meteor might help leaving the seal in on the chaincase side because they had a terrible felt seal setup

As Norm says leave the outer seal in place it will help prevent leaks in the primary chaincase, unless it is one with the breather in the crankshaft venting into the primary then it will make no difference.

Thanks Neddy ,Norm and Dennis C Looks like It will be best to use the unsealed bearings for this model thats good as I think I have one with out the seals
Duffel