Topic: Please help identify this part on CB550 K1

[CB750wannabe]

It's plugged with gray sealant.  You can see a groove in the sealant from the chain. 

[carnivorous chicken]

It's a countershaft seal. When people switch over to o-ring chains it rubs against the seal, eventually causing a leak. I had a 550 that I put JB Weld over and it held it in (and a thin washer behind the sprocket to stop it from getting worse). When it leaks oil will drip down to the shifter.

[CB750wannabe]

Not the countershaft seal.  I just discovered that the part I'm referencing is the mainshaft oil seal.  Some previous owner put a lot of sealant over it.  And it had a o-ring chain.  I will test to see if leak is coming from mainshaft oil seal or the shift shaft seal.  Here's a pic of a mainshaft oil seal that goes behind all the gray sealant in my first photo.

[carnivorous chicken]

Not the countershaft seal.  I just discovered that the part I'm referencing is the mainshaft oil seal.  Some previous owner put a lot of sealant over it.  And it had a o-ring chain.  I will test to see if leak is coming from mainshaft oil seal or the shift shaft seal.  Here's a pic of a mainshaft oil seal that goes behind all the gray sealant in my first photo.

Sorry, yeah, that's what I meant. If it's not leaking I'd let it go, but change the chain and or put a small washer behind the sprocket (I'm sure someone will chime in how that changes the geometry of the chain, but it worked for me for years).

[bryanj]

Cant remenber which shaft but its a case split to change as its got a peg on it and def caused by O ring chain