chadleehonda

i dont know if this is true, but umm what do people mean my balancing the crankshaft when you go with smaller and lighter underdrive pully..and what about adding lighter flywheel?

delsolproblems

The crank pulley on many Honda motors is also a harmonic balancer. Check google or wiki for info on how it works. If you replace the balancer with a non-balancing pulley, any imbalances in the rotating assembly will get worse. Even a slight imbalance can create vibrations that reinforce other vibrations, multiplying the effect at high RPM to the point of dangerously throwing off the motor's timing or even shaking the motor apart. The flywheel doesn't have a built-in harmonic balancer and so upgrading it doesn't create the same problem.