FMF Q on a 400F/426F?

I currently have a 99 yz400f with WB E series exhaust. I have the quiet core insert and five disks but I am going to be enetering a enduro in March and I need it to be under 96db's. I dont think the e series is going to get it done. I am considering the original version of the FMF Q series to put on the bike to get me through the race with out breaking the bank. Problem is I have heard of some 426 guys having trouble jetting there bikes for this exhaust. any body had trouble with the original Q and jetteing on there yzf's?

PS: If anybody is interested in The E series muffler and WB head pipe both in excellent shape email me they are for sale or trade for a stock 400/426 sysem, they do me no good in California.

I have one on my '99 yz400 and it works great. The metal strap to mount it is a pain (hint: use a longer bolt to mount the strap, makes it much easier to align the holes and compress the strap).

It mellows at the power a little bit on the bottom, but it goes like heck on the upper end, and is quite. I've had to richen the pilot jet a little, and probably need to do it a little more since it pops a little on decel on cold days.

I have no regrets.


my dads works pretty good weve had no trouble with it

Thanks for the replies, I think I will go with the E2 so it will match up to the header pipe.

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