I am looking to buy a new silencer for my 400EX, and I need your help. I like the WB E-Series and the new FMF Powercore IV-2 (squared) silencers. I would like to know, which is louder? How much louder than stock? About how much hp will I gain? Thanks a lot.

 

White bros a lot louder than stock. FMF is supposed to be as quiet as stock.

 

i have the WB e-series on my y2k 400ex and it is significantly louder, not so much at idle, but when you really open it up it barks! its sounds awsome. i mean its not super loud or anyoing not like a harley loud. but you can buy a quite core insert and not loose any power and tone it down. not sure of the exact HP figures but you can definatly tell once you install it. last wednesday i was at a mx park and there was about 25 ring ding bikes and my 400 and you could here the 400 above them all! good luck.
adam y2k wb 400ex
92 fmf blaster

 

Does anyone know about the Big Gun silencer? If so, how does it sound with the Spark Arrestor in it? Does it give a great power increase?

 

First of all, how much power can you add just replacing the silencer vs the whole exhaust on the 400EX? I tend to believe the stock headpipe is quite trick for stock... so I plan to replace only the silencer and save $200. On the other hand, I'm getting a complete Big Gun exhaust for my dirtbike (it's stock headpipe is a joke). For a good article on Big Gun on a 400EX check this out (you can even click and hear the pipe):

http://www.off-road.com/atv/400ex/big_gun.html

 

My friend uses a WB E-Series for his Warrior and I used a Powercore IV SA for my 400ex and they are both loud. I installed the new Supertrapp IDS2 with 18 discs, K$N filter, 8 air box vents, 160main jets (we have warmer weather in the Philippines),450/451 Web cam, hardwelded rockers and I really had fun. The sound was not as offensive as before but if you're looking for power I don't think you would attain it with a silent pipe.

 

It's not the Power Core IV that I was talking about. It's the new quieter Power Core IV-2 (squared). It's suppose to be a lot quieter than the original. Sorry. I should have been more decriptive. Thanks for all of your help so far.