Fork Oil questions for '78 YZ-80

Hi All,

I'm fixing up my old 1978 YZ-80 for my son. It will make a great new-to-him ride just as soon as I get it back into running trim.

The fork oil is 31+ years old and I have a sneaky hunch that it probably could use a change. I don't have the service manual so am hoping somebody can advise me on the following:

- What is the recommended change procedure?

- What's the recommended viscosity fork oil to use?

- What's the oil capacity of each fork?

The fork seals seem OK, they are not leaking despite their age.

TIA for the replies!

Daryl