What is this thing here?

[Lockcuff]

Sorry to sound so dumbe but what is this, its on a 78 gs550e, look for the green arrow. it has a leak, and id like to fix it, but want to know wat it is first.
Thanks

[Billyboy]

Looks like your cam chain tensioner.

[Lockcuff]

Ok, thanks I was wondering that too, there is this little spring thing on it that looks broke. was just wandering.
Thanks

[Billyboy]

Your welcome.

[bwringer]

Here's how to clean that nasty thing up and fix the leak that attracted all that dirt:

http://bwringer.com/gs/camchaintens.html

Your part numbers might be different, so make sure you look them up for yourself. However, the cam chain tensioners all work pretty much the same so this should help.