08 Crank Bearings
 

Why do the main bearings in this engine I am working on have seals? The replacement that came have them as well. How do they get lubricated with seals on them?

They are trying to run lower premix ratio's in Europe for emissions. I forgot all about this. That means they are probably in my bike as well. I wonder if you can just remove the seals.

Any reason to not remove the inside seal on the replacements?

I won 't be putting it back together till this weekend or early next week so it will be fun to gather some opinions on this. I hope they are not in my 07.

I can't see why not. Would one not want to remove both seals so that the crank seals are lubricated?

'08+ went with sealed crank bearings, grease inside. Personally, I like the old school stuff, just feel better about it knowing I use plenty of good oil and its one less thing to fail. There were a couple failures reported here but nothing widespread. From what I heard you can just use the '07 bearings as the cases are the same, but I have not verified this. The open roller/ball combo was sound. I'd like to know of a significant population of high hour '08+ bikes with original bearings. My issue with the seals is what does all the fuel additives do to them overtime?

I already have the bearings. Hate to return these to get new ones if I could just pry the seals out. Any thoughts Dusty?

The seals will just pop out. Another method would be to carefully lift the seal edge away from the inner race and pour a bit of synthetic 2T oil into the bearing. This will mix with the grease and should extend the lifespan. Considering that 2T oil lubricates at small ratios, the undiluted oil should work well.

Is the roller bearing Nj206 ec3? does it still have a polyamide cage?
It cracks with age due to gasoline use.

Regards

Not sure about the roller but its probably the same since '05. I'm at 200 hrs and have had no problems.

I would not just pop out seals. If your going to use what you have, I'd remove the seals and clean out all grease, so its like a new open bearing. Also, make absolutely sure that the oil holes in the cases exist and are open.

I'd just get the proper open stuff and install that. The roller is rated at a higher load than the ball bearing. You could also look into ceramics or hybrid ceramics, the guy I get bearings from is big into this now. Nice thing about ceramics is they require much less lubricatiion and are more heat tolerant, which would make them less prone to seizure should something go wrong, like jetting, air leak, etc.