Harmonic waves can travel thru the drive train and thru the crank. If there is nothing at the end of the crank to absorb the wave, it will travel back in the opposite direction to meet the next wave. This causes the unfavorable harmonic vibration. The first thing to take the abuse is the oil pump gear and you know what happens when that breaks. ALSO, pulling weight off of the crank that close to the center line will add ZERO horsepower or rpm capability. Don't fool yourself on this. Think of how big and thick the counter weights are on a crankshaft. The harmonic balancer is just another externally added counterweight that happens to absorb negative wave energy. Honda engineers were not stupid or naive. Don't try to out think them in this case, use a harmonic balancer.

Personal experience...We abuse the drive train launching at 8000 rpm and shifting over 10,000 rpm. The aluminum under the flywheel bolts started to eat away and the flywheel started to vibrate back and forth. When it came completely loose it sent a shock thru the crank so strong that it snapped the key holding the harmonic balancer in place. The balancer spun on the crank, put the crank fired ignition out of time and shut the motor off. When pulling everything apart, we found that the shock wave had actually also bent the crank to the point where it was unusable again. This proved to me the useful purpose of a harmonic balancer. We run steel flywheels now, BTW.

UPDATE: Since writing this, we have started selling the ATI line of dampers for the following reasons..

1)The ATI damper continues to dampen vibrations to unlimited rpms whereas the fluid unit loses its effectiveness at about 7000 rpm. Check the graph below.

2)The ATI is 1.25 pounds lighter than the fluid unit.

3)The ATI is rebuildable.

4)Viscous fluid dampers are sealed. The inertia weight can become locked by bearing failure or, more commonly, from the silicone turning to a solid mass. Your first warning of damper failure will probably be a broken crankshaft resulting in the replacement of your damper and the engine.

5)ATI units are used on all NASCAR engines as they were designed specifically for high performance engines. Their design is fail safe, efficient and available for any engine application. They are SFI certified.

6)Bolt on crank trigger wheels available with the ATI.

7)ATI was able to build a custom damper for our race car. It is for a S2000 engine with a Chevy bolt pattern to help us connect our dry sump pump to our engine.

8)Much more detailed information here.