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"Generic" Engine Bearings

jimboFosho

New member
Joined
Mar 17, 2011
Location
San Jose
Moto(s)
MOAR!
What are the thoughts on using non-OEM bearings for main and transmission bearings? (OEM in this case meaning the moto OEM - Yami, Honda, Suzi, etc)

I am going through a bottom end rebuild and as I started to price out a full set of bearings, things really started to add up...so I started thinking about going to an industrial bearing supplier. I admit to not having a ton of experience with bearings but they appear to be industry spec'd so my question is if anyone knows if OEM's do any up-screening of industry bearings or anything special to your run-of-the-mill bearing. Would yall have any concerns about running a 'generic'.

I would be limiting selection to reputable mfgs - Koyo(the OEM bearings), SKF, Timken, NSK, etc.

If these were wheel or shift linkage bearings, I wouldn't hesitate going to a non-OEM source but considering the higher consequence and effort to replace these puppies, I figured I might as well ask before deciding.

Thanks! :ride
 
Bearings of all sizes are available in different ranges of quality. McMaster Carr will sell you military spec bearings that are probably above the quality of the originals.

Just guessing but the price would be in the ballpark of OEM and. . .McMaster will have 'em on your doorstep in one or two working days.

I rebuilt many, many industrial electric motors with their units and haven't had a bearing failure since.

And, there are other bearing specialty companies out there just waiting to do business with you.
 
We are talking about cartridge ball bearings here correct? If so the manufacturer numbers should be on the races, and any decent bearing supplier can give you an equivalent.

McMaster is certainly an option but their prices are rarely the lowest
 
Yea I took note of the stamped numbers and the standardized sizing system and that is what started me down this path.

I'm thinking I'll end up at a local bearing supplier. Mcmaster/Fastenal/Grainger don't have super great selection when it comes to matching all the different bearing. And I have yet to pull all the bearings to price them out and see just how much savings potential there is there.

From my initial searches, asking which bearing mfg was better sounded like it started to turn into the types of discussions you get when asking what's the best kind of engine oil - everyone's got an opinion.
 
As long as the part number matches you should be okay. I would not try to substitute one that is the same size but marked differently, because it can be rated differently.

For reference I recently did this on a project bike and ended up buying OEM than trying to save 10%. No question there. But maybe you can find them for way cheaper.
 
As long as the part number matches you should be okay. I would not try to substitute one that is the same size but marked differently, because it can be rated differently.

For reference I recently did this on a project bike and ended up buying OEM than trying to save 10%. No question there. But maybe you can find them for way cheaper.

This.

If a bearing is marked with an OEM specific number or code, it likely has a different spec than anything you can buy over the counter.

I just went through this with trasnmission bearings for my bike. The manufacturer confirmed a specification (grease and seal tolerances) not found elsewhere.
 
I've used Koyo on my Sv motors with no problems. As boney pointed out, there are exceptions.
 
I ran into an unexpected problem trying to use generic Japanese bearings instead of the actual Honda-supplied main bearings on a GB500 RFVC engine. The problem was the non-Honda version did not have a generous enough radius inside the inner race. This prevented the bearings from seating all the way up against the crankshaft, which prevented the crankcases from bolting together. Essentially the bearings made the crankshaft too wide to fit into the cases. In the pic below the Honda bearing is on the left-

IMG_0010.jpg


-Bill
 
Beware of fakes, regarding the more popular brands.
If the price looks really good, while shopping around. . . .
 
I ran into an unexpected problem trying to use generic Japanese bearings instead of the actual Honda-supplied main bearings on a GB500 RFVC engine. The problem was the non-Honda version did not have a generous enough radius inside the inner race. This prevented the bearings from seating all the way up against the crankshaft, which prevented the crankcases from bolting together. Essentially the bearings made the crankshaft too wide to fit into the cases. In the pic below the Honda bearing is on the left-

IMG_0010.jpg


-Bill

Wow who would have thought
 
The Bearing Agency in SF South of Market will probably have anything you need in stock and will get it if they dont' and if you catch them on the right day you can all talk your ears off about bearings and all the fun stuff about them.
 
I ran into an unexpected problem trying to use generic Japanese bearings instead of the actual Honda-supplied main bearings on a GB500 RFVC engine. The problem was the non-Honda version did not have a generous enough radius inside the inner race. This prevented the bearings from seating all the way up against the crankshaft, which prevented the crankcases from bolting together. Essentially the bearings made the crankshaft too wide to fit into the cases. In the pic below the Honda bearing is on the left-

IMG_0010.jpg


-Bill

Doesn't seem like to difficult a problem to remedy.
 
The Bearing Agency in SF South of Market will probably have anything you need in stock and will get it if they dont' and if you catch them on the right day you can all talk your ears off about bearings and all the fun stuff about them.

Thanks for the tip! If I can get up there during normal work hours I’ll try to stop by.
 
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Same tools you'd use to port a cylinder head, on the bearing to increase the size of the radius.

I remedied the problem the easiest way, by buying the correct bearings. Reshaping hardened steel would require grinding, exposing the balls and races to abrasive particles. Personally I would never trust being able to flush every particle of that grit from the bearing. Plus the left side bearing is pressed onto the crankshaft, meaning that removing it involves pulling against the outer race which compromises the balls and races so once pressed on and then removed it needs to be replaced.

-Bill
 
I remedied the problem the easiest way, by buying the correct bearings. Reshaping hardened steel would require grinding, exposing the balls and races to abrasive particles. Personally I would never trust being able to flush every particle of that grit from the bearing. Plus the left side bearing is pressed onto the crankshaft, meaning that removing it involves pulling against the outer race which compromises the balls and races so once pressed on and then removed it needs to be replaced.

-Bill

This. In all respects.
 
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