Just installed my FMF pipe on my sp 500 sounds good without the tuneable disks. THe directions suck,not sure how the disks work when i put them on and tighten up the bolts it just seals off the exhaust and kills the motor. Seems like there needs to be a gap between the disks or something. Any help would be great .

 

Either you have the disks on wrong or you have the screws way too tight. The disks need to face the back and the screwes dont need to be that tight. There is supposed to be a very small gap between every disk and the more disks you use the louder it is and the more it will breath. You also have the quiet core and heat shield. Some have 9 disks and some have 12-13 disks.