Civic EG

Hello everyone...
As I have already informed the forum I am building a b16a2 all motor ...I would like to ask , should I change the pulleys to lighter ones ? If I change the crank pulley will I have any problems? I will be using a lightweight flywhell 5.4 kg

No, they're a waste of money. Changing the crank pulley is especially bad. The OEM pulley has a rubber dampener inside. This is to prevent a catastrophic vibration that occurs at a particular RPM. An aftermarket crank pulley will eventually crumble. Wont damage your crank though. That's a myth as far as Hondas are concerned.

Some low revving Hondas don't have the rubber dampener.