I bought one for my 01 426. It is very quiet, no noticeable loss or gain in power..you hear the motor a lot more than with the stock exhaust. I took my Q exhaust off to ride wherever Idont need a sparkarrestor because the bike just sounds better. I wasn't impressed with the silencer for the price, $330. Really not an impressive part. But it did do the job of quieting it down.
I have had a Q on my ’01 YZ 426 for about a two months now. It did seem to richen things up a bit. It is definitely quieter, no question about that, this is especially noticeable at lower RPMs but it is probably more pronounced with the throttle open.
I have tried the stock can and the Q back to back on one occasion. I think the Q does steel some power down low, but it really shines up top. IMO it revs just like the stocker, maybe even a tiny bit better. I wouldn’t be surprised at all to discover the peak HP is the same on a dyno.
But I do think it robs a small, but noticeable, amount of low end.
I paid $290 for mine, but that is still too much. A two-stroke pipe seems more complicated to build, and is much cheaper. I recently had an entire exhaust, from the catalytic converter back, installed on my truck for less than what I paid for this pipe. I just don’t understand the pricing on these 4 stroke exhausts....
If I didn’t need a SA I would have just left well enough alone. But I am happy so far with the Q, and given the relative price of other systems would say it is worth the extra twenty (forty??) bucks.
Finally, I have heard of problems sealing with the header, but this seemed to occur on 400s only. I think the 426 header may be larger, because mine fits very snug and does not leak at all despite what must be more back pressure than stock.
I just wanted to add that I had a PC T4 on my ’00, and it robbed the top to pay the mid. I liked this at the time, but after riding my ’01 stock for a bit I found myself loving the rev that I sacrificed with the PC. The FMF Q loves to rev too.
If you like to short shift you may not like the Q at first. If you like to spin it a bit longer in each gear then you will be happy.
But to answer your question Tex, I don’t know for a fact that overall power isn’t reduced but it wouldn’t surprise me if this WAS true. I guess that is a bonus because, personally, I did not believe it when I bought it, I just wanted to try something a little quieter for a change.
On my 01 YZ426, there was not enough room for thre gasket between the header and silencer, so i went with out it and had a snug fit with no noticeable leaks. Were you able to use that gasket or did you just run without it?