I have read test after test after test, and I still cant decide which full exhaust system would be best for a 400ex. I am wanting one that will give gains throught the whole powerband. Right now I have narrowed it down to CT racing, curtis sparks, white brothers E series, and maybe HMF. Im kinda leaning away from HMF as the tests I have read said that HMF helps alot in the low to mid range but gives next to nothing in the top end, where as the other 3 pipes listed give good gains thorughout the whole powerband. All I am planing to do to the bike is K&N air filter and lid with outerwears and then the full exhaust with a re jet, with a possible stage one cam and a 10:1 piston down the road. I am haveing a hard time decideing which system would be best. Most of the tests I have read either picked the CT racing or the curtis sparks, but I just cant decide so any help would be appreciated. I am wanting to have alot of low end grunt and get up and go to it but I am also wanting some improvments on the top end as well.

 

I would suggest to you the curtis sparks...For my 450r I am either going to be going with the curtis or dasa(not sure if they have dasa for the 400)...The ct racing pipe is also a good pipe and I think whatever one you choose you will be happy with and will see an imporvement...The only thing that you may be woried about is DB levels and if they aren't a concern for your area go ahead, get the exhaust and rip and it will feel alot better...If you need any tech help or anything let me know.

 

Does anyone else have an opinion on this?

 

I have a HMF slip on on my 400ex but i am thinking about goin to curtis sparks full system i have heard they are great on 400s if u have nemroe question just let me know