Need help identifying a part

[KitchenDonkey85]

I don't have a picture of it but there's this rubber piece that fell when I was removing the exhaust and diff parts on my bike. I will just describe it, it has a cross groove on top and it's black. Like a grommet but not sure? I looked around but can't spot where it goes. Appreciate any ideas!

 

[JourneyToFit]

I don't have a picture of it but there's this rubber piece that fell when I was removing the exhaust and diff parts on my bike. I will just describe it, it has a cross groove on top and it's black. Like a grommet but not sure? I looked around but can't spot where it goes. Appreciate any ideas!

well, it does sound a lot like a grommet for a wiring harness or cable.
Sometimes, near the exhaust or diff, wires need to pass through a frame hole or a cover, and those grommets often have grooves on top to help them seat properly or hold the wire.
you need to trace any loose wires in that area

 

[Strapingmyself]

Considering it's a rubber piece if it's not from the wiring harnes, then it's probably like a buffer or something like that. Is there any rattling? metal on metal that wasn't there before?

 

[Beatrice]

Why do manufacturers still use mystery rubber bits with zero labeling? You'd think by now every part would be tagged or keyed to a diagram. Instead, we're stuck reverse-engineering bikes like it's 1985