Sorry, my bad. The bearings are ball, not roller, i.e. the most common bearing found around.

The camshaft has two of these bearings on both ends. Actually, one of them is not at the end, but just behind the cam-chain sprocket. At least this is what I saw by lifting the head cover a little, as I couldn't remove it completely without dropping the engine from the frame at least a little.

Plus, when you untighten the bolts of the cover the cam-chain pulls one end of the shaft, which rises the other and it's somewhat tricky to put it back together while everything is on the frame. I hope I wouldn't have to do that (dis)assembly again for some years :D