Is 60,000 yen enough for 4 days in Japan?

I'm spending half a day in Osaka then Tokyo and finally Kyoto within four days via the 3-day Willer Bus pass (I'm spending 2 nights on the bus and have already bought my pass). Hostel accomodations in Osaka is also covered. The 60,000 yen is mainly for food, trains, sights and some light souvenir shopping. Accomodations and highway bus is covered. Will I make it?

Are you serious?

That comes to 15,000 yen per day.It is definitely doable.

Erm? What and where are you eating at??

Even if you eat A5 Grade 10 Wagyu beef for lunch and dinner daily, you'll still have cash remainding for breakfast and whatever else.

Are you sure you didn't mean 6,000 yen?

Sightseeing and local city transport usually works out to around a few thousand yen per day, so if your long distance transport and accommodation are already covered then 60,000 should be fine to cover your sightseeing, light shopping and even a nice dinner out (not Kobe beef everyday though, that'll easily eat through your budget in just a few meals ;)

If accommodation and bus are already covered, it is doable - now the question is whether you can enjoy all those locations within that short period of time.

Yes, that is enough for regular sightseeings, meals, and local transportations. You mentioned highway bus, so I believe you won't be taking Shinkansen between Tokyo and Osaka/Kyoto. If you will be taking Shinkansen, your budget will be on the tighter side.