Ms391 Crank Bearings

[r1stgei]

So I popped out the crank today to change the seals... I noticed the bearing on the clutch side was completely open. The balls fell out on the ground. I looked at the bearing on the flywheel side and it seems to be sealed and also seems to have a metal inner ring in it... I cannot for the life of me find an metal ring on the other side. Are these bearings different? Or are they the same and Maybye I missed a part fall out?? Either way I think I am looking a my getting a new one.

Any help would be appreciated !

Thanks

 

[Justin Taylor]

Someone could have already replaced 1 side

 

[DND 9000]

No the bearings are not different. The inner metal ring is needed to hold the balls in place. Maybe you have missed it while it was falling out, or is it still inside the housing somewhere?

 

[deaves61]

I used echo bearings in mine think they were a cs600 bearing I think they are better than the oem stihl.

 

[sawfixer]

I did a write-up on 6/4/2015 about rebuilding my MS391 which had Fag (Made in France) main bearings with plastic retainers. The retainers failed and spit the balls into the crankcase. The replacement Stihl bearings are still the crappy plastic retainer type and cost $40/each. These are specialized bearings that I believe daves61 is correct, are shared by the Echo CS600 series. I decided to use high quality 6202 bearings with steel retainers which have a smaller OD but have the same ID and width. I used copper pipe as sleeves to make up the OD difference and the saw has run well for several years. The posting I did in 2015 should provide additional detail.