125 Sachs Crank Bearings

[Ron]

I'm not familiar with the type of crank bearings used in this motor. They seem to have inner and outer races with gaged balls. My inner races are very close to the crankshaft counterweights and it seems like a special tool will be needed to remove them. First of all,how are the races removed for replacement, and are the stock bearings the best way to go?

 

[Kip Kern]

Ron
The crank bearings are M-20 and are available from Al Buehner.  You will also need to borrow a inner race tool to remove the bearings from the crank.  Warm the bearing races slightly before removal and installation.  Makes the job easier....Good Luck

[Ron]

Hi Kip, Thanks for the info. Do you know what type of inner race tool is used? I'm thinking it must be some sort of two piece shell puller. Any idea where to find one?
Thanks again,
Ron

 

[dave hussey]

I am not a professional mechanic.  The following information is from my own experience, so YMMV. The special bearing puller tool is MUCH preferred, but I did not have access to one, so I did it this way: with the crankshaft WELL supported by oak blocks, I used a cold chisel ground to a narrow taper, and lightly tapped it with a hammer into the small gap between the bearing race and crank counter ballance all around, which slowly became wider as the race moved. Note that this will probably damage any shims you will find there, but they will have to be replaced anyway, when the new bearings are measured and spacing recalculated. Obviously you would not use this method if you were not going to replace the bearing races. BE CAREFUL to not distort the crank shaft alignment. Runout should be rechcked and adjusted after assembly of the new races. I froze the crankshaft with dry ice and the new races slipped right on. Good luck. YMMV so use this information at your own risk...
Dave H.

[Kip Kern]

Ron  If you contact Al Buehner, he may have a loaner.

 

[kc]

How I pull bearings without special tools is.  Wrap race with brass sheet, clamp w/ bear separator, and pull with standard bearing puller.  Use heat as needed.
kc