The old ZS motor is quite well known for spinning it's main bearings don't think it helps that half teh ZS owners just seem to sit at shows bouncing their cars off the limiter.

Anyway, The 1.7 from a Puma is supposed to be pretty straight forward but the later Yamaha derived 1600 Zetec really isn't a bad motor at all. Certainly nothing like the old Zetec 1.6 which was about as nice to have a genital warts