hello all, I am not new here but havent posted any thing cause i didnt have a quad untill this past friday when i bought my new xx and I am vary happy with it, still doing the brake in process and vary happy with my new quad.


any way back to buisness... some time down the line i will put a new exhaust on and after reading and reading i have narrowed my choices down to 2 exhaust, one being the fmf, I am new to off road exhaust but i know fmf has been around for some time, how ever i have also read about the huge hp gains of the motoworks exhaust.

well iam not sure which one to but.. and was looking for input to help my decision, can any of you tell me which you would choose if you only had these two to pick from for your 700xx and why ?

thanks in advance
james

The FMF is super nice, but I can't honestly say anything bad about any of the muffler manufacturers at this time.

I have a 2nd hand Two Brothers Racing slip on that I bought from a forum member and I really, really like it a lot. It's pretty loud though. (and I love it)

On a previous quad I had an HMF muffler and I liked it equally as well but it seems as though the one I had shown below would have been a PITA to repack when the time came.

http://i82.photobucket.com/albums/j254/gwwaddle/400EX/100_4994.jpg

thanks for the heads up, loud is good........ how about the power gains from it ?

When I first put them on I giggled like a schoolkid.

3rd gear pulls awesome now. Wheels go in the air easy without clutching.

I just got my FMF 4.1 also, but have not installed them yet. When you guys talk about the loudness and the hp gain, is that with or without the spark arrestor?

I thought I had seen somewhere the claimed hp gains....anyone know if they were they with or without the arrestor?

I just got my FMF 4.1 also, but have not installed them yet. When you guys talk about the loudness and the hp gain, is that with or without the spark arrestor?

I thought I had seen somewhere the claimed hp gains....anyone know if they were they with or without the arrestor?

My 4.1 didnt come with the arrestor installed. There is a ring in the end of the pipe, but its not holding anything in place. The hp gains that FMF claims for the 4.1 are without the arrestor.
The 2bros pipe Scuzz has is loud, with or without the arrestor, but its a nice deep loud.

My 4.1 didnt come with the arrestor installed. There is a ring in the end of the pipe, but its not holding anything in place. The hp gains that FMF claims for the 4.1 are without the arrestor.
The 2bros pipe Scuzz has is loud, with or without the arrestor, but its a nice deep loud.


I thought that ring at the tip was the arrestor. So it's not?
I emailed Leeson's, where I purchased the FMF, and he replied that the system comes with it.

There is trail park in PA I want to ride at, and they require the arrestor.

Dave, do you know what the db is without the arrestor on the full 4.1 system?

The park requires max of 99.

That's at idle right?

I'm pretty (almost positive) you'd be ok.

I know the two brothers is borderline.

thanks for the heads up, vary intrested in which one would be the best bang for the buck

Dave, do you know what the db is without the arrestor on the full 4.1 system?

The park requires max of 99.


Ara, I will try to get a reading tomorrow at idle and let you know. I am pretty sure you will be ok. At slow speed the 4.1 isnt loud, but when you open it up, look out.

what about the power core 4 ??

Dave, do you know what the db is without the arrestor on the full 4.1 system?

The park requires max of 99.

Ara, at idle it was reading 91db, with the wind blowing. You will be ok with the restiction of 99db.

Ara, at idle it was reading 91db, with the wind blowing. You will be ok with the restiction of 99db.


Thank you very much, Dave. I also called FMF and they are claiming 102 without the arrestor, but maybe that's at WOT.

The PC3 I ordered from Fuel Moto came loaded with a map for the FMF full system but mapped with the arrestor. So I guess the motor will run a little leaner without it. I'll let you guys know once I get some time to install everything. The bike is been sitting since I got it over a week ago and I have yet to ride it a foot, and I got all these parts laying on the floor ready to get installed. You think I would ride it and see how it runs first? Nevaaaaaaa

Thank you very much, Dave. I also called FMF and they are claiming 102 without the arrestor, but maybe that's at WOT.

The PC3 I ordered from Fuel Moto came loaded with a map for the FMF full system but mapped with the arrestor. So I guess the motor will run a little leaner without it. I'll let you guys know once I get some time to install everything. The bike is been sitting since I got it over a week ago and I have yet to ride it a foot, and I got all these parts laying on the floor ready to get installed. You think I would ride it and see how it runs first? Nevaaaaaaa


And the park requires a spark arrester anyway. Anyone know how much HP is lost with the arrestor?

You wont lose much at all with the arrestor installed. We metered mine at idle today, but without the wind, it could be 2-3 db more. 103 seems like what it will be doing at a good running speed.

well any chance we can stick to topic ? how about the 2 bro's can is it worth the buy ?

I think so.

As I mentioned before it'll be easier to repack than the less expensive HMF sport due to the rivets that the HMF has.

what about the power core 4 ??

Dont know much about the Powercore 4, other than i have seen a few on other makes of quads. They are quite a bit quieter, but still a nice sound

what about the power core 4 ??

I have the powercore4 with header and it is mid 90's DB. It is pretty quite at idle and is loud but not obnoxious at wot. I am very happy with it and I'm not a fan of louder the better exhaust. I had the Q4 silencer before this one and it had a nice sound too.

I'm not sure on the accuracy of my decibel meter, but I just got "decibel" from the App store on itunes for my iPhone and it said idling was 105db lol

notice any change in power from the exhaust you where using befor and once you put the powercore4 on ?


the more and more i think about it maybe i should waite for the motoworks exhaust

I'm not sure on the accuracy of my decibel meter, but I just got "decibel" from the App store on itunes for my iPhone and it said idling was 105db lol

Jeff, gives this a shot, its a digital sound meter from Radio Shack that sells for $50. use it and take it back (keep receipt and package). Dont forget sound measurements are taken from (i believe) 20" away.

http://www.radioshack.com/product/index.jsp?productId=2103667