Excellent find sideways! Indeed the crank pully does have a a rubber ring to reduce and dampen vibrations from the crank. Older Honda motors such as the b series for instance were machined accordingly to match the crank and effectively balance it. Our s2000 pulleys however do not have this.

Also to some degree even if the pulley was changed to an aluminum one, the belt will still reduce this vibration much like holding your hand on a tuning fork and trying to allow it to resonate.

If the crank pulley was without a belt it could in fact be more vulnerable to resonation again using a tuning fork as an example, like striking it and allowing it to resonate until the energy is displaced elsewhere

 

So use the pulley if you want. You dont want to be told no, so just go do whatever you want.

 

Toda sells a lightweight pulley set. ASM Autobacs talks about constantly being sold out of them in Japan. I think people here are paranoid about using them.

 

It has nothing to do with being told no...

Do you think its good for your engine to boost it? No!

Was your engine designed, reinfrced, and intended to be boosted? No!

Did you still do it even though you know your engine wears faster and could have serious engine damage? Yes!

So where is your logic? Im not arguing to use it or not to im simply arguing the facts! I have yet to install it and I want to be able to justify its issues rather than just say "Everyone on s2ki said its bad but nobody has any data to support it"

 

Since some people seem to think I am being naive I found an answer actually worthy of posting that I was in search of in the first place.

Again I was never pro-aftermarket crank pulley I just wanted a good explanation as to WHY specific to Hondas from someone who knows their $h!t

Please feel free to comment and add anything else you find!

From Laskey:

Harmonic Balancer rather than Billet Pulley

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.

Heres the link: http://www.laskeyracing.com/shop/harmonics.htm

 

Here is more food for thought...

Changing the original crankshaft pulley can have negative effects if the replacement pulley is not manufactured properly. A crankshaft or accessory pulley that is not machined or balanced properly can cause severe damage. For most domestic V8s a harmonic damper is necessary to absorb crankshaft vibrations. Early to mid-year V8's kept the pulley and damper as separate components. Most late model V8s now integrate the damper and the pulley into one part. For small displacement engines found in many import and domestic vehicles (4.0L and under) the original crankshaft pulley only serves to quiet noise vibration and harshness (NVH) you hear in the occupant compartment. Although it may look like a damper on V8's engines it serves no protection function to the engine. It is the same as the baffles and resonators found in the intakes and exhausts systems of most cars today that serve to make the engine as quiet as feasibly possible. The first things most enthusiasts do is install high flow intakes and exhausts; the quieting function is eliminated.

http://en.wikipedia.org/wiki/Underdrive_pulleys