is this muffler worth a crap to a stock 400ex. is it better than a stock silencer? how many discs do you use? i just cant see a silencer made like this working but please someone enlighten me. right now it is louder but seems to have hurt top end. i have all 11 discs in it now. do i need to jet to get top end back or throw this thing away? help!

 

I used all the discs with mine and it didnt seem to hurt the top at all but it did improve the bottom a little ( with stack jetting)

I then richened the needle one clip and went one size on the main and pilot ( pretty much just helped the starting ability)

after that the silencer broke around the weld where the cone connects to the canister, FMF sent me a new pipe and for some reason it seemed to like the stock main jet better than the one oversized ( go figure )

as of this past weekend this silencer has broken and im in the process of sending it back to FMF and may try to persuede them into sending me a powercore 4 instead just so i'll have something different

GOOD LUCK