Bought an '82 GS.. 5 speed.. 12A.. engine was 'locked up', I figured with 90K on it I'd learn something by pulling it apart and rebuilding it... I'm cleaning rotors and one face of the forward rotor had 3/16" of hardpack carbon and beneath that the face looks like the moon, pocked and undulating but with seeming good integrity. Not sure which way to go. Everything else looks fine. I'll keep digging around here for ideas and ask questions when I intelligently can.. fun as hell..

central ohio
mallen1

 

Same i feel like these engines are much more fun to work on than pistons!