mega max muffler, HELP

[diesel-mech]

My dads 2000 300ex has a fmf mega maxx pipe. It sounds like it is choking the engine. It has absolutly no "bark" to it and the power just doesn't seem to be there. We've tried jetting changes. No good. His old trx250 was stock and I think it had more power. We bought the quad almost new with this pipe on it and it has always seemed weak. No top end at all. I wanted to add more plates but where do you get them?

Any ideas?

[JDiablo]

prolly if you get a better pipe you will notice more power...that is prolly one of them pipes that takes away power :rolleyes: and put this in the powertrain forum next time

[K_Fulk]

See what happens when you take the plates off.
The disks could be on backwards too ... Iv'e seen that done before on these. There is also may be a flat piece with a small tube on it under the disks. If they installed that it kills the power too.

[tinner]

Do you have the quiet core in ?? I used a Mega Max on mine, I had twelve discs in it. It worked better than the stocker, but not after any mods...way to restrictive. Like what has been previously mentioned...take off the end cap and discs, and try and run it. See if that helps your problem. If it does, you may need more discs ( I don't know how many you have in). Anyone who carries FMF should be able to get the discs you need.

[04'400ex'er]

Originally posted by 300exrida
prolly if you get a better pipe you will notice more power...that is prolly one of them pipes that takes away power :rolleyes: and put this in the powertrain forum next time I agree with gettin a new pipe but this is the powertrain forum.

[JDiablo]

Originally posted by 04'400ex'er
I agree with gettin a new pipe but this is the powertrain forum.


ooppssws my fault,i prolly looked at a thread that was in the pen forum and clicked this one...my bad:D

[speedy400]

Mega max's arnt that bad. FMF's website they have dynos that say they work much better than stock, mine deft. worked better than stock on my 400ex back in the day, but then when I got the 416 and such I needed a higher flow muffler. If you think it needs more flow you can make a new endcap plate( the flat piece on the end) and put a few holes in it.-darren

[diesel-mech]

The thing is I had a friend with one on his dr350. I rode it The power was great, it sounded healthy. Now I haven't ridden a 300ex other than dads. His trx250 ran great all through the power band. The 300 feels and sounds weak. I realize the dr350 is a bigger engine by a different manufactorer but I can't see how it would be such a drastick change. I had a 230 zuki back in the day that had more balls. Something is wrong. I told my dad to try some of your suggestions, I haven't talked to him to see how they worked out. But thanks for the help so far! If you have other good ideas let me know.

[TC426EX]

Do yourself a favor and take that thing off, sell it, and replace it. Megamax exhausts are JUNK. Absolute CRAP. My buddy had one on his 300ex before he sold it and had nothing but problems with it. VERY minimal power gain IF any at all (someimes ive heard of them being WORSE than stockers just like someone posted earlier). He sold that megamax to a guy on ebay that is prolly hating his life right about now and got an HMF. What a NIGHT and DAY difference especially on that bike. Overall, I am not impressed with any of FMF's four stroke exhausts. The titanium 4 is pretty good, and their 2 stroke stuff rips, but for 4 stroke I think they need a couple more years in the R+D lab....... DEFINITELY get rid of that megamax though and youll thank me later...

[diesel-mech]

Originally posted by TC426EX
Do yourself a favor and take that thing off, sell it, and replace it. Megamax exhausts are JUNK. Absolute CRAP. My buddy had one on his 300ex before he sold it and had nothing but problems with it. VERY minimal power gain IF any at all (someimes ive heard of them being WORSE than stockers just like someone posted earlier). He sold that megamax to a guy on ebay that is prolly hating his life right about now and got an HMF. What a NIGHT and DAY difference especially on that bike. Overall, I am not impressed with any of FMF's four stroke exhausts. The titanium 4 is pretty good, and their 2 stroke stuff rips, but for 4 stroke I think they need a couple more years in the R+D lab....... DEFINITELY get rid of that megamax though and youll thank me later...

Thought about going that route but pipe cost alot of bucks. Dad is old school and won't pay a lot of money for a pipe. Like I said he bought it with this pipe. if he could had the stock pipe it would be on it. If he gets a new pipe its if I buy it for his b-day or x-mas

[400rednEX]

i went from an annoying t-4 to a megamax2 and noticed very little power loss, now with more disks it's probably the same, except you can pass db tests if needed. they come with a quiet core, so it's probably in there choking it off.

[TC426EX]

Originally posted by diesel-mech
Thought about going that route but pipe cost alot of bucks. Dad is old school and won't pay a lot of money for a pipe. Like I said he bought it with this pipe. if he could had the stock pipe it would be on it. If he gets a new pipe its if I buy it for his b-day or x-mas


Dude, just throw it on ebay and someone will buy it!! Do a little research and see what they are going for and make your starting bid accordingly. Then you can take the money you get from it plus a little bit more and you should be able to buy any pipe you want for cheap off of ebay. HMF, Sparks, Pro Circuit, LRD, they got them all for SUPER deals. I bet if you sell it on ebay you would not have to invest much money at ALL. Maybe like 50-75 bucks thats it. Do what you want, but I would do anything necessary to get rid of that and ebay is the easiest way. Plus you can get your new pipe from there too for dirt cheap...

[sbexrider4life]

try taking the disks off of the muffler once to c if there is an increase and if it sounds hollow like a lawn mower almost then u might need to repack it

[diesel-mech]

Originally posted by TC426EX
Dude, just throw it on ebay and someone will buy it!! Do a little research and see what they are going for and make your starting bid accordingly. Then you can take the money you get from it plus a little bit more and you should be able to buy any pipe you want for cheap off of ebay. HMF, Sparks, Pro Circuit, LRD, they got them all for SUPER deals. I bet if you sell it on ebay you would not have to invest much money at ALL. Maybe like 50-75 bucks thats it. Do what you want, but I would do anything necessary to get rid of that and ebay is the easiest way. Plus you can get your new pipe from there too for dirt cheap...


Ok if anyone sees an FMF megamax muffler on ebay BID REALLY HIGH!!!!!.LOL: blah: ;)
I did buy another pipe for him off ebay, RCA It was cheap! we are going to run it for a while to see how it performs. If it does well I'll try selling them both and buying a good pipe.
He tried some of the tips you gave me, Running the pipe wide open worked great but the neighbors cows won't give milk. ITS LOUD!!

[TC426EX]

wtf is an RCA????

[diesel-mech]

Originally posted by TC426EX
wtf is an RCA????

Don't know fever heard of it before but it looks a lot like a cobra or dg muffler :confused:

[dirtmomma]

Geez you guys are scareing me LOL I run a Megamax w/ motor mods & I've never had a problem w/ it except for it cracking where the pipe meets the silencer. Does your Dad have an aftermarket head pipe?? Maybe thats whats wrong w/ it the stock one is really small. Well good luck w/ it & for more discs like said before call FMF ;) I run 10 in mine :)

[diesel-mech]

The header pipe is fmf too. Its a pretty big pipe compared to stock. I was just over there and forgot to count the plates. I'll call him and get back on that

[K_Fulk]

Wheres greenville ohio.

[diesel-mech]

Originally posted by K_Fulk
Wheres greenville ohio.



Bout 30 miles north of dayton, on the Indy border


A buddy of mine in Cali used to say "Ohio??? what states that in???"
You just reminded me of that and I had to share it;)

[K_Fulk]

Alright just wondering, I dont get to that part of the state much, or I probly would have been around there before.