So I did a few searches, and got different results. Here's what I got going on.. I put an aluminum ud pulley on a few years ago.. 6 or 7.. I'm in the middle of an opti install right now and I'm coming across some things about having to use your factory crank pulley on top of the ud pulley? I was under the impression that these pulleys were neutral balanced, so I never even thought this was necessary. Now like I said, this pulley was installed years ago, and I haven't had any issues regarding it. I guess my question is how important is having the factory pulley on there? Do I need to go to a junk yard and try to find one? (Mine is long gone)

 

It's a harmonic dampner-not a balancer. It cancels out vibrations harmful to the crank. Yeah, should be on there.

 

Good enough, thank you

 

Better to buy a new one....anyThing in a junkyard is at least 19 years old.