My 96 Accord (with same engine) makes the same exact sound after all of the belts have been replaced. I too, did not notice it until after the timing belt, etc was replaced. I have no idea what causes it, but I've driven over 10,000 miles since the new belts were installed, and it has caused no problems. I read somewhere that it is pretty common. Although I have no substantial proof to back up this theory, I think it is caused by the greater tention of the brand new belts on the 'old' pulleys, causing them to emit that 'whine' Just my $0.02, perhaps the gear heads can be more elaborate.