Check out the February 2003 issue of "ATV Rider". They have a pipe comparison test on the Z400/KFX400. If you compare their findings on 6 different 4 stroke pipes and compare it to the Dirt Wheels test of the HMF you'll find that the HMF is ridiculously loud. Don't forget that sound Db levels are logrithmic. When you compare 107 Db (HMF) to 95-97 for a typical White Brothers or Big Gun or FMF....the HMF will have your neighbors wanting to shoot you!

 

Hey thanks for the info about loudness of pipes. I guess it back to rethinking everything I thought I had figured out. Red Spring or Black or Both? HMF or BIG gun or ? I guess what I really need is a pipe with a quiet core that can easily be removed that way if I want to sneak around quiet I can or when I go to a place where noise doesn't matter I can take it out and rip. Anyway I will figure something out.

 

The HMF pipe for the twin is NOT as loud a the single cyl. motor's, don't know why, but the Grizz,400ex, Rap, are all way louder than mine even with the core removed, The 650 with the quiet core, measure's 95-96 db's.........

 

trx450, I have an idea about something but I need to think about it first. Im sure you will like the idea.

 

Staak,
That's good to know...I wish one of the mags would do a comparison test on sport/utility pipes. It's clearly not only the pure sport quad riders out there that are looking for good pipe info!