Cam belt idler bearings (1100)

[Reno]

Having a noise from the right side of the engine (only when warm) that sounds like a ball bearing issue. To me, just from listening at idle, the frequency of the growl sounds like it would be associated with the cam rotating speed which is not particularly encouraging. But the belt idlers show some sign of corrosion. I did try to home in with the screwdriver against the ear trick but that wasn't particularly conclusive. My plan is to replace the idler bearings anyway and see if that fixes it. I haven't taken her apart yet and had a couple questions that I could use some help with in preparation:

1) Bearing P/N. Some variations out there for recomended SKF replacements. Options like bearing clearance and seal type. Does this application use a "normal" or a "C3" spec clearance bearing?

2) How many do I need? Can all four idler wheels be re-bearinged (some confusing guidance out there)? Is there one or two bearings per idler?

Thanks, Reno

[Reno]

Nevermind, it appears that these rollers are sealed units that can't be re-bearinged. Previously it seems the adjustable idler (used to set belt tension) had replaceable bearings. My engine ('08 MTS 1100s) has sealed roller units permanently affixed to an adjustable movable bracket just like the fixed rollers. None of them are rebuildable.

Fixed rollers: $54/ea
adjustable: $72/ea

At Ducati Omaha

I'm starting to have my doubts that one of these is the problem anyhow. Gonna try a proper mechanic's stethoscope this evening to try and learn more.