Crank Bearings

[70MXer]

I'm learning as I go so bare with me, I have a 1976 KTM MC5 250 and I'm replacing the rod assembly and will probably replace the crank bearings. I checked with Al and he doesn't stock the FAG M-25 three piece bearing but said the bearings are available but a little expensive. My question is have anyone in the POG ever considered using or used a modern ball bearing instead of the three piece bearing? I see some guy buzzard that says he used the modern type bearing without any issue. Any direction would really be appreciated.

On another note, I really appreciate the fact how everyone in our POG steps up and offers their knowledge and help when someone is in need. I'm lucky to be part of this group and just love what our Penton group is about. Thank you!

[Daniel P. McEntee]

If you do a search on the subject, you will find much written on it both ways. Some have had single race bearings work, others have not. The reason for the three piece bearing is to allow a minor mis-alignment in the two case halves. It's a lot of work to rebuild the bottom end and get things correct, so why risk having to start over if single race bearings don't work out, and other problems and costs arise from the process? I have read many threads here with tales of woe but occasionally some one gets lucky and they work. I would take the time and spend the extra money and use what came in them OEM. You will find them with plastic cages and with brass cages, and maybe it's just me, but I would specify brass or any metallic cages if possible.
   Type at you later,
   Dan McEntee

[Larry Perkins]

Do the Original kind of three piece as the engines were designed for that and they always work.  No bad stories here and there with those.  Do those and you probably won't live long enough to have to do them again.  Look how long the first ones lasted. My 2 cents worth.

Larry P

[G Ellis]

I have the M-25 3 piece bearings in stock. I had some made, $140.00 a set shipped. I can send you some photos. You can text me or call me at 217 260 0237

[70MXer]

Larry/Dan,I agree with staying with the original bearing design.

G Ellis,that would be great if you would send me some photos. I just text you, thank you.