I WANT A PIPE FOR TRAIL RIDING( TIGHT WOODS TRAILS). ON THE TRAILS I RIDE I HARDLY EVER GET OUT OF FOURTH GEAR. I HAVE A 2000 400ex, BONE STOCK AT THE MOMENT. NEED SOME INPUT BEFORE I SINK THE MONEY ON ONE.

 

I have a brand new 2000 400EX as well--just got it last night--and am looking hard at the FMF Power Core IV-2. FMF claims it's Forest Service approved and increases power without the increased noise, and the Powerbomb headpipe addition also increases flow by 10% but at the same time lowers the noise level--sounds as though it's too good to be true. If anyone is running this system--if it's available yet--please comment.

 

I have a 99 400ex that is bone stock, I went and drilled the holes in the exhaust like Pam said in the early posting. This pass weekend at a race I had a chace to drag race it on Sat with another 400 the same as mine except he has the White Brothers E-series pipe. The quads were dead even in all the races. We even changed riders and we still had the same results. I was going to order a pipe but after that no. Now I can go to the nationals and run the stock class,maybe? Why buy a pipe when drilling the holes give the same results and the quad is still very quiet.

99 400ex

 

The 2000 400EX doesn't have the same restrictor that the 99 model has (I looked), but you can supposedly change the end cap for a little better flow--search the Performance forum under Pam's signature and you'll find the reference for where to buy it.

For a little free HP, make sure you check the throttle adjustment that has been mentioned here many times, mine still has about a 1/4 of an inch showing, but will leave it as is until it's broken in.

 

tprender, which post has the details on drilling the stock exhaust? Is it louder afterwards?