Sealed or not sealed wheel bearings?

[brentn]

Was doing some maint last week on my 10 450 and noticed that the front and rear wheels do not use sealed wheel bearings. I couldn't believe it, normally I could have sworn that yamaha used sealed bearings but maybe I was wrong.

Behind the oil seal you can clearly see the "balls" that make up the bearing and the grease that they are surrounded it.

Found it really nice and easy to pack in some more grease, but what scared me was that if that oil seal were to go, water/dirt would get in there and the bearing would go extremely quickly.

Is this a stock feature for 450's? Is this a 2010 thing, or do all models have this?

[runester]

All years...

Same with swingarm bearings, so be careful.