One of the French sentences ([#135126]) doesn't match :
Je n'ai pas les moyens de m'acheter un vélo. (present tense)

I think that "could" could be used to express the present tense:

e.g. We couldn't afford an apartment right now.
http://sentence.yourdictionary.com/afford

It's a conditional mood, isn't it?
We couldn't afford an apartment right now. = Nous ne pourrions pas nous permettre d'acheter un appartement maintenant. ?

I could not afford to buy a bicycle. = Je ne pourrais pas me permettre d'acheter un vélo.

Dem japanischen Satz nach zu urteilen, ist die Vergangenheit gemeint. Aber denkbar ist wohl beides: Vergangenheit und Konjunktiv.

Though, "Je n'ai pas les moyens de m'acheter un vélo" could also mean "Je ne pourrais pas me permettre d'acheter un vélo".

@CK
Thank you for your comment. The French sentence ([#135126]) says "I don't have the means to buy a bike".

You could (note the tense) consider that this "could" is either a conditional, a past (as I translated here http://tatoeba.org/fre/sentences/show/808116) , but also a present.
It is often an idiomatic way to say that you actually can't right now, in my view.
And this is also the case in French, actually (see my latest translation)

@sacredceltic
Don't you think that "Je n'ai pas les moyens de m'acheter un vélo" would rather be a translation for "I *can not afford to buy a bicycle", or do both match?

that's what I was trying to explain : I think both match.

And this is also the case for French : I think you could translate the conditional « Je n'aurais pas les moyens de m'acheter un vélo. » by either a conditional or a present, because it is actually also a rethorical way to express that you actually can't right now.

You could consider it is short for « « Je n'aurais pas les moyens de m'acheter un vélo, si je le voulais actuellement. »

As in English : "Would I desire it now, I could not afford to buy a bicycle."

Oui, je comprends, merci pour votre explication !