Many people are replacing perfectly good and serviceable STD main bearings.
If your original STD bearings look good, no visible scoring or obvious damage, then you might not have to replace them if within specs.

A bore gauge is the proper tool to check the clearance but a decent quality digital or dial type inside caliper will tell you if you're in the ballpark. If you do not have these tools a trip to the local machine shop will be worth the effort. Most will check the bearing clearance at little to no cost.

Min bearing clearance is .0024 & Max clearance is .0042
The STD crank journal OD is 2.000
So if your clearance is .004 or less then there is no reason to replace them.

The availability of quality US made STD main bearings is limited. There are some "import" bearings out there but the ones we have seen were not made to the correct specs. Right off the boat the clearance is already at, near or beyond the Max specs.



This STD main bearing can be used front or rear on all CCK, CCKA, CCKB, B, P & N series Onan twins. Onan used this exact bearing originally from the factory for the front and rear but the parts book will call for a 101-0805 one piece bearing for the front.



If you need to replace the thrust washer use part # 104-0575


101-0804 Supersedes/Replaces :

101-K420
101-0420
101-0450
101-0805

STD = 2.000" or 50.80MM

Made in U.S.A.

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