I just bought a new 200 400EX with the big bore kit already installed. I am running a 440cc with 11:1 wiseco piston, other than that the bike is still stock I am looking for a good race exhaudt system. I am told that I need something that flows really well. Better than the 1.5" dia stock headpipe. Do you have any suggestions?? I have been looking at Powrell, Curtis Sparks,Graydon Proline, LRD, Big Gun, White Bros. I also would like your recomendation on who makes a good cam. I know you work for Powrell, but if you think they have the best set up for any of this let me know. Thanks very much. By the way my name is Jared.

 

Jared,

Sorry I haven't replied to your e-mail -- It's been one of those weeks!

Anyway, what we've found out on the 400EX is that most of the aftermarket systems that are quiet enough for public lands are all about the same in performance increase -- about 5 - 8%

If you are just racing the bike (mx, flat track or tt), you can get away with a race exhaust. These are WAY LOUD, but on the 400EX give a very impressive increase in HP (up to 15%).

As far as the cam goes, you can go with an aftermarket one if you'd like a little more midrange and top end. The down side is the price, you would need to get a hardweld cam ( $120 - $160), heavy duty valve springs with Titanium or Cromoly Retainers (no aluminum) ($90 - $120), and get your rocker arms Hardfaced ($200 - $250). All this for about a 10% gain. Not much bang for the buck.

If you're trail riding, you'll probably be faster with the stock cam. It would help for dunes or racing tho.

Hope this helps you out!

 

Thanks very much for the advice. I am going to definately go with new cam since I already have the big bore kit. One more question who makes a good race exhaust??? Thanks again.

 

I have a Curtis Sparks and I really am happy with it, but like Pam said it is very loud. It looks real good too, all Chrome with aluminum canister. It costs about $350, I also bought a foam filter and jet kit from Curtis.

I haven't seen the Powroll, but I am sure Pam has all the details.

Adam Smith
99 400EX

 

I've seen the Sparks exhaust, it works well and looks great.

Any of the open-style meg exhausts seem to work well -- except for the twin-header designs! The goal with an exhaust is to get it out FASTER, and hot air moves faster than cold air. That's why you see ceramicoated headers (they keep the exhaust hot and movin' faster). By splitting the exhaust into two parts, the exhaust temp is greatly reduced. Not good. Anyway, sorry about that tangent, all of the "Race" systems I've seen appear to work equally well. The Sparks system is the best looking for the price (the Powroll system is only $40 less, and isn't chromed).

I've also seen the Graydon system. It also looks good -- haven't tested it tho.

Pam

 

I was woundering if that $350 includes chroming. How does the sound compare to a WB or somthing similar. A lot of the places I ride don't care how loud it is but then there are a few places I ride like behind my house were the neighbors wouldn't like it much and the Curtis Sparks are laso cheaper. Also does Curtis Sparks have a web site I would like to see some pics of their pipe.

 

Yes, like I said before the Sparks exhaust comes chromed for $350. It is very loud though even quite a bit louder than the Big Gun. Subjectively, speaking though if your neighbors are bothered by loud noises what difference is the WB gonna make. At least if you buy a true "race" exhaust you get some power for your investment. It had been my feeling that most of the aftermarket exhausts available dont amount to much, and Pam has proof to back that up. Of course, before she stated the facts it was just my opinion and speculation. I hope people pay attention to what she says, I know I would be very irritated if I dropped over $300 in an exhaust that only gives a marginal gain in HP!

Adam Smith
99 400EX

 

How do you guys feel about the CT racing exhaust. I've heard a few people comment good on it and i like the looks, it comes chromed with spark arrestor for $400

thanks

 

Anyone,

What do you think of megaphone exhaust systems like the White Bros. E-Series? I've read, in both ATV and dirt bike magazines, and heard from owners, that compared to round-silencers, megaphone exhaust systems make more dyno horsepower. However, they've said that in the real world megaphone systems don't perform. I also read that megaphone systems provide more high rev/top-end power, which relates back to the "dyno power." What do you think?

 

Here's a little tid bit for the discussion, At the time I bought my Curtis Sparks Pipe, about 1 1/2 years ago, he was sending them out to be nickel plated, rather than chromed. During that time I have had no discoloration or bluing due to heat. His welds are clean as a whistle & his work is impeccable. Since most of my riding is in National Forests I had to go with a Supertrapp silencer. The down side of Sparks is that he's a one-man shop (or at least was) . He's primarily an engine builder & as such is following the circuit during racing season & is closed except for an answering service. Consequently, delivery times are extended.I have his tel # if any one wants it. He's in Bakersfield.