Welcome. The ring is just a washer to keep the bushing in place. You could just clean yours up and reuse it. You could paint it to keep it from corroding again. If you look at the part on Partzilla they have a "related fitment" where they show all the years/models that used that part.
Related Fitment
This Honda 51413-461-003 PLATE, BACK-UP fits the following models and components:
Honda Motorcycle 1982 CB750F A - 750 SUPER SPORT Front Fork
Honda Motorcycle 1981 CB900C A - 900 CUSTOM Front Fork
Honda Motorcycle 1981 CB750F A - 750 SUPER SPORT Front Fork
Honda Motorcycle 1982 CB650SC A - NIGHTHAWK 650 Front Fork
Honda Motorcycle 1981 XR250R A Front Fork
Honda Motorcycle 1982 CB900C A - 900 CUSTOM Front Fork
Honda Motorcycle 1980 CB900C A - 900 CUSTOM Front Fork
Honda Motorcycle 1981 XR500R A Front Shock Absorber
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."
1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)