Main Bearing Life

Max as far as performance goes I only noticed a slight difference between Maxima and Yamahalube R . I used the Maxima (one bottle ) because it was given to me, the difference being it didn't run as clean through entire throttle openings. This might have been do to jetting on my part. So I went back to Yamahalube R. I've never had a failure due to Yamahalube and I used it on a heavenly modified 100 HP plus built Yamaha Waveraider motor built by Harry Kliem.That's all I've ever used with that one time test of Maxima. I recently had my modern YZ crank and lower end done all OEM bearings also and I was told it didn't need it done by measurements taken.None the less I wanted it done for peace of mind.

Absolutely there are differences in bearing quality, look at the codes stamped on the bearings indicating the tolerances, C codes are what I look for in a quality bearing, Keep in mind you may need to look at the fitment on the crank end or cases, also, Loctite make a product that can help, haven't used it In quite some time, but I think it's called bearing lock?

Kevin, before you shell out money for ceramic bearings, you might want to tear down the motor and make sure you haven't spun a bearing in the cases. My 84' RM did that and I had to find a new(er) set of cases.

We just had a crank let loose in a low hour rebuild of a 83 CR250. All OEM Honda bearings, seals and rod kit in it.

Like someone else mentioned, make sure you didn't spin a bearing in the cases. Common problem with the early CR250M Elsinores. Go to put new bearings in and they just fall into place...

I didn't mean to imply that it was a oil related issues as Maxima is used by so many with positive results. The OEM versus after market comparison will always be debated. I personally buy the best quality that I can afford which some times is after market.

FYI: C codes have no relation to quality. It is a code that defines a tolerance, where a certain C code, ex. 3, would be better for a specific application, than a 4 would.

But as with alot of things, you usually get what you pay for.

Ceramic bearings only offer lower friction and slightly higher load ratings but are more fragile when it comes to dirty environments. I would not suggest them for a bike unless you are building for HP.

You could up the class of bearing or maybe look at how you installed them. I always use temperature to install my bearings and have been very successful.

Always use a crankshaft install tool-to pull crank into bearing-with support on the inner race,
no hammering, or deadblow(not your wife).

Yes, the cold bearing, warm case is a must

Bought a set of OEM Yamaha mains way back for my 79 YZ250 that was in my Champion short tracker.

Falicon prepared crank. Got it together, and the crank end could be rocked back and forth with no flywheel like the bearings had a million miles on them.

Ordered another set. They were not sloppy like the first set, but had the plastic type ball separators / cage in them.

The engine was entirely fresh. One night, at the races, it was running hard, and then popped / backfired once and it quit. The plastic separator / cage had broken, all the balls rolled together on the ignition side bearing.

It basically threw the engine out of time, hence the back fire. That was after about 20 races on those bearings.

Got a good set of speed rated C3's , some real bearings, and it was very reliable after that. I was running Blendzall.

Had heard rumors that some of the chemicals in that oil were known for attacking seals, plastics.
That may have contributed to the plastic cage failure. Although, with the C3's it never gave lower end trouble again .