Cam roller ain't rollin' right

[sert duc]

One of my cam rollers is not rolling in sync with the others - there is a link to a video on the bottom of this post. Notice the left roller compared to the right one.

Here is the long story:

My '04 620 has been in various states of disrepair going on 2 years now. It's probably seen about 350 miles in those two years (I've been fighting back issues for a while). In that time it has been sitting under a cover outside my apartment in sunny Southern California.

I recently drained the tank of old gas + sea foam, changed the fuel filter and the fuel level indicator. I charge up the battery, put in some fresh gas and she starts right up. I've noticed recently that the cam rollers have accumulated some rust on them (I run open belts and unfortunately stored her outside that way), but I've never noticed any problems. Now one of the rollers isn't rolling right. As its connected to engine internals I shut her off and let her be.

Where do I start diagnosing this problem? Pulling the roller and removing the rust is a first step but I'd be worried to damage any engine internals is the problem was more serious than a little rust. Any help would be appreciated.

[Speeddog]

Replace with new or good used part.

They aren't repairable, and removing external rust won't solve the internal problem.

[sert duc]

Which of the parts would need to be replaced?

[Speeddog]

In that diagram, part #16 is what you need.

It's up to you to connect that with the right part number for your bike.

[sert duc]

Part #45120211A. $54 - not absurdly priced.

You've been a tremendous help - thank you!