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lipped crank bearing

i have an inner drive side crank roller bearing with lip on the bearing cage for the M20, which way should the lip face? and whats its purpose

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Re: lipped crank bearing

If your cushion drive nut comes loose it stops your crank from moving over and chewing up your timing side.

Re: lipped crank bearing

Could be wrong, but I assumed it was to reduce the chance of excessive (any) axial load on the rollers; possible if the bearing spacer gets worn.


open side towards the crankshaft, otherwise how would you get the crank in with rollers attached? :wink:

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Re: lipped crank bearing

On the M-types I can see no other function of the lips then preventing the outerrings from creeping out of the crankcase.

I guess it is a heritage from earlier models where the crank was not pulled up to a ballbearing but the lips were used to position the crank axially.

On the driveside the lip can actually lock up the crank if the 1" spacer is worn [like most of them] and the rollers are pushed hard up against the lip when the nut is fastened.

On the B-series where there is only a rollerbearing on the timingside it indeed prevents the bearing from creeping to the case. In the M-type the ballbearing prevents this.

I would say no need for lipped outerrings on the M20 unless your worried about creeping them out of the case.

BR Michiel

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