G1 "Absorber"

On the subject of my G1 engine work (to be continued in the other thread), what does the "absorber" absorb? Is it needed, or nothing to worry about? (Here it is depicted on the TNT Carts site, Item #8: Yamaha G1 Cylinder)

It now sits on my workbench in about seven pieces ... one large, and six smaller broken off pieces. Just wondering if I should try to find another one, or just reassemble without it.

Thanks in advance,
Ogre