it does keep up the revs, remeber i also put on a lightened flywheel too. with less rotating mass engine will spin quicker. also frees up hp

 

No, it doesn't. Without the extra inertia of the heavy flywheel and pulleys, the engine will slow much faster. Faster revs and keeping up revs are two completely different things.

 

Kai is right. w/ the less rotating mass, the engine will rev quicker, but it will also fall much faster due to lack of inertia. I have replaced just my crank pulley w/ a lightweight unorthodox unit, and will be replacing the clutch & flywheel this weekend (clutchmasters aluminum flywheel). Just getting rid of the parasitic drag attached directly to the crank is what I have heard you want to do. I can't really tell a difference w/ just the new crank pulley on there, but when I pulled the factory one off, that think weighed a TON compared to the UR.