This is the tool that holds the clutch housing (a.k.a. flywheel) in place so that you can remove or install the clutch nut when replacing the clutch nut O-ring or main seal. (It's actually a tool originally made for airheads but also works on the early Ks.)
I found it here for $14 no tax, free ship:
https://claussstudios-com.checkout.weebly.com/store/status/6373df33a55bb/confirmationBut it's not really necessary to have this tool because you can just stick a block of wood up in the corner to keep the flywheel from turning:
