Hi,
It's a little difficult to see in the fiche.
If it's the single outlet model that screws onto the male tank connector, there's not much to rebuild. The little textile(maybe it was naugahyde) washer between the body and the selector barrell does not appear to be necessary, at least I am not, and the only other parts are easily accessed and cleaned.
I rebuilt a completely non working and ugly one by just cleaning and reassembling it.
I was surprised to find that the part number is still listed by Honda if you want to replace it. Otherwise get another off of ebay.
All best,
Ben