7 hour lay over worth a trip to Shibuya?

I have a 7 hour lay over in narita, my flight lands at 12:30pm and departs at 7:45. Do you think it's worth taking a trip to shibuya?
I am so confused about this train too

You will probably have 2 hours if everything goes smoothly. Assume 1 hour to clear immigration and get to train and 1.5hr to get to shibuya station. So multiple that by 2 for roundtrip which is 5 hours.

Is is a domestic flight you get to Narita by to connect to an international flight?

Or is it just a transit?

If you can get out of the immigration by 13pm, as it depends on what day, you can reach Shibuya by 14:34 via Narita Express. In order to catch your flight, you have to get back to Narita by 17:30, I assume. You can get Narita Express at Shibuya at 16:16 then.

So it looks like you have only 90 minutes or so to do something in Shibuya. Whether it is worth or not, it is you call.

Narita Express costs you 3,110 one way.

Narita Express goes to Shibuya directly from Narita Airport.

http://www.jreast.co.jp/e/nex/index.html

time table
http://www.eki-net.com/pc/jreast-shinkansen-reservation/english/wb/com...

You could visit the town of Narita, if they still have a free bus to the town from the airport (and back). The main street and a big temple are interesting.

It's an international flight to Los Angeles, CA, USA
So is it wise to travel out? Is the subway only in Japanese characters or is there English translations?

Is there something specific you want to do in Shibuya?
Forget the Narita Express. Use the Keisei railway Skyliner. It takes about 40 minutes to NIPPORI or UENO. From NIPPORI to SHIBUYA on the Yamanote line takes about 25 minutes.
For shopping, you can find most everything at Ueno and if you want to sample Japan, Nippori has the old traditional west side and the modern east side.