Exhaust Mods

Does the FMF Q4 come with a head pipe or do you have to cut the stock pipe? By looking around the EXUP valve, it appears the whole stock pipe and muffler is one piece and there is no slip joint from the factory... What do you have to do to make the FMF work with the stock head pipe?

There is a clamp just forward of the EXUP where the pipe seperates from the stock head pipe. Then slip on the FMF. The FMF will come with an adapter sleeve to fit the stock head pipe, or you can buy the FMF header and replace the whole stock system.

10Cup wrote:

PS: It also uses the stock header which I want because the smaller diameter header helps the low end of the powerband, while the bigger pipe lets the engine rev more it also takes away some torque. Because I want all the low end I can get for my trail riding, the stock header stays. FYI.

Actually the Powerbomb header has a smaller diameter headpipe in front of the "bomb" section but gets bigger than stock past the "bomb". I feel the low end grunt was greatly improved over stock...

I went riding with some buddies yesterday, mine was the only one with stock exhaust. I was surprised at the difference in loudness of the aftermarket exhausts. The KLX250S with TwoBrothers slip on was by far the loudest and quite annoying. There was a KLR250 with an unknown brand exhaust that was loud but not as loud as the previous. What really surprised me was the DRZ400 with a Yoshimura slip on. It was very quiet but had a nice tone. I had the chance to ride behind all three bikes. I've heard Yoshimura was very loud for the WR's. Does anyone have similar experiences, comparing to other bikes? If I knew that the Yoshimura sounded as good on a WR as it did on the DRZ, I would buy one right now. Thanks, All. Safe riding!

Howdy. :)

I have a 2009 DR-Z400SM and a 2008 WR-250R.
I've had stock exhausts on both and now have full aftermarket exhausts on both.

The larger-displacing DR-Z400 is always going to have a deeper and more bass-sounding tone than the smaller-displacing WR-250R.
It's due to how the physics works, kinda' like how the buzzing wings of a big ol' bumble bee sounds deeper than the itty-bitty ones of a mosquito.

I'm using FMF full exhausts on my two bikes.
The DR-Z has the Q2 muffler while the WR has the Q4.
Both have FMF Powerbomb head pipes.
The DR-Z sounds nice and bassy and not too loud at all.
The smaller WR sounds higher pitched, but still not too loud.

Whatever brand exhaust you get, do youself a favor and get rid of the airbox flapper (costs nothing) if you haven't already, and budget the money for a fuel injection programmer to richen up the fueling.
Your bike wil run mucho better with more power across the board. :)

mtb wrote:

asheville thumper wrote:

So let me get this right, are you saying that if I just do the Q4 and the programmer w/o doing other mods I would have a noticeable improvement? I hate to spend the money, but if I have too...well then...I must, for the benefit of the bike and all.

Yes I believe so... the weight loss and less restricted exhaust air flow (with proper fuel tuning) will create a significant performance gain (my dyno shows it all... a proper tune gets me 1 more extra horse)... not to mention that your bike will "sound" much faster

actually the cheapest way to enjoy your bike more is tyre+sprockets change

This bike is my toy. I don't ride it to save gas. I ride it to have a good time. It almost never gets highway time. Mostly just hooligan riding in my little city. What is a good gearing to switch to?

I am running 12/47. Good grunt power but still able to hit 70mph,65 mph comfortly.

IAmABug wrote:

I am running 12/47. Good grunt power but still able to hit 70mph,65 mph comfortly.

Yeah that works for me. The only time I'd see 70mph is if I were running from the cops.

StreetGhost wrote:

IAmABug wrote:

I am running 12/47. Good grunt power but still able to hit 70mph,65 mph comfortly.

Yeah that works for me. The only time I'd see 70mph is if I were running from the cops.

If you're on an X - I'd say that's bullshit.

You'll be running 70mph no problem, and wishing for more.