Is it worth fixing my 1990 Sportrak engine


Having replaced a burnt out valve on my 1990 Sprotrak EL (70000Miles only)at Christmas and lost compression again on the same cyclinder, i'm guessing that my rings have gone and would be very surprised if it was the valve again. So do i try and fix the rings and overhaul the engine or just get new bottom end. Bearing in mind that it is quite a young engine in mileage terms.

Interested to know if anyone has ever replaced the rings, put new bores in or know a reputable company that can rebuild the block and whether its worth it or should i just buy a limited mileage lump from Japan??