factory exhaust

[barry.sims2]

ya'll help this old man out. seems to me its a waiste of money to buy a new muffler.my 400,runs a lot better just taking the spark arester out. i'am stock except for a 13 front sproket.razor2 tires front & back.now my question,do i need to rejet , just running with out the spark arester.don't want to go to lean and burn a piston. i do a lot of fast trail riding and hare scrambles. thanks for any help.

[F-16Guy]

The difference between a stock exhaust and aftermarket is that a stock exhaust uses mechanical baffles, where most aftermarket are straight through with a perforated core baffle. Removing the stock tip will open it up a little, but the mechanical baffles still restrict flow. Most engines are on the lean side, so it wouldn't hurt to bump it up. Maybe try a 150 or 152 main, and a 40 or 42 pilot will help with cold weather starting. Have you seen these?:

http://www.amazon.com/99-09-Phoenix-Performance-Exhaust-Insert/dp/B001R5CLNG/ref=sr_1_13?ie=UTF8&s=automotive&qid=1242743123&sr=1-13

It might give you the performance you want while keeping you legal.

[Snipe]

Yeah they run bit lean, when I did this same thing it ran even leaner. Required a rejet aftermarket exhaust and jetting you will fill a dif depending on the exhaust and jetting.

After putting on my white bros I had to learn to ride again first ride out hit the rev limiter in the first 4 gears was used to it reving longer.

[deathcorefan2]

i know that RCR makes an exhaust for the 400ex. give him a call and ask how quiet it is, it is only 200 bucks.

http://www.rittercycle.com/honda.htm

[barry.sims2]

thanks for the input. i'am going to take the small nossel out of the end cap,then i'll rejet a little richer. rather spend money on good front shocks,think that will speed me up,and help with endurence.