Do I need to remove all bearings before cleaning crank halves?

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6/23/2018 2:56 PM

So i split the cases on my 98 yz250. I got the crank bearings out since I’m replacing those. I now want to clean the case halves really good. It was a pain in the ass removing the crank bearings but I did it since I’m replacing them.

Can I get away with Leaving the other bearings in if wash the case halves with some soap and warm water. Followed by compressed air wd40 etc?

I don’t want to damage the bearings trying to pop them out.

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6/23/2018 3:09 PM

Proper way to do a rebuild is to replace all of the bearings. So yes, take them out and replace them. Why do a half assed job?

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6/23/2018 5:34 PM

kb228 wrote:

Proper way to do a rebuild is to replace all of the bearings. So yes, take them out and replace them. Why do a half assed job? ...more

X2

Paw Paw

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6/23/2018 6:40 PM

I have done what you're sayin many of times without any issues, the proper way is to change all the bearings sometimes you're on a budget and have to make do with what you have

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6/24/2018 12:53 PM

Clean with kerosene or desiel if you are going to clean them. Don't use water. Water leaves room for corrosion. Also do not blow dry bearings, you will spin them too fast and cause possible issues. Just rinse with kerosene and brush or scrub them with a tooth brush.
GoYamaha

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6/24/2018 5:01 PM

Go to your local bearing supplier with the old bearings, you will be surprised how cheap new bearings are, not even worth trying to save them..... any kind of media cleaning means bearings need to come out...

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6/27/2018 2:19 AM

Well I’m convinced lol. I’m going to replace the bearings. I just need some help ID’ing the right bearings on the schematic.

Photo

The red arrow is pointing to #2 (part 93306-20540-00)

And the green arrow is pointing to #24 (part 93306-20562-00)

On this schematic
https://www.ronayers.com/oemparts/a/yam/50043f10f8700209bc78e024/transmission

Correct?

Also I’m just using Ron Ayers for the parts numbers. Does anybody know of a cheaper place online?

Thanks

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6/27/2018 12:20 PM

I've done it both ways. Granted I would rather replace all bearings but since I do motor work as a favor for others that don't have much money it isn't always an option. Usually if case are real bad I try and get as much as I can done prior to cracking them open. Pull engine, plug intake an exhaust & pressure wash with degreaser/Totally Awesome and maybe some Alumibrite(careful with this as will dull any steel). Possibly soda blast if really bad.
I have never had a bearing that checked out good during disassembly go bad in in transmission so take that for what it's worth. I have done more bottom end rebuilds than I can count and try to do the best job I can within budget constraints of whomever the owner is............

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