Topic: What is this...

[ealanm]

...and how do I get it off?

I finally started the rebuild on my CB750 race engine.  Where the alternator goes I found this thing, shown in the photos.  I assume it's just some kind of cover for the sprag clutch, but I'm at a bit of a loss as to how to remove it.  Anyone got advice?  Is this thing common on race-prepared engines?

It also seems to be damaged, perhaps due to a problem with the sprag clutch, but I expect to find out more about that once I get it off.

[Bill/BentON Racing]

Try a rotor puller,screws into threads on end,looks to be machined down pc. with starter clutch.Bill

[ealanm]

That turned out to be simpler than I thought.  The screws from the back side go almost all the way through, so that there was only a couple of turns of thread visible on the outside.  At first I didn't think I could get a puller engaged in them.  But it did work, with a little care.

This engine has no alternator, so I assumed it had been replaced by this piece.  But on closer inspection it looks like the piece I just removed could be the taper that the alternator normally mounts on.

[cbr954]

I believe that is a stock alternator that the outside was machined off.  Should be able to remove it just like an oem alt.

[Retro Rocket]

Probably left there for some flywheel effect....