After talking to everybody reputable I could find and feeling more cut off than Ted Kennedy Bar hopping on St.Patricks day. Opinions are becoming consistent. Performance vs. quiet!! It's very hard to get both. Twin pipes versus. y pipe?.....Twin pipes have a sharper spike in the power ban. Y pipes have a broader spike. (E.g. , wider torque curve) I am leaning towards the Y pipe, Why? You say, Because Honda knows what its doing and I am just gonna push it a little further. Hondas twin head pipes are 20 inches long before they join to a single. DG’s head pipes are 25 inches long before they join. Yet both exhaust systems are the same length. That extra 5 inches on the head pipes pays big dividends to low end torque. Upon entering the single pipe we have our first pulse. This is where(In the single pipe)the exhaust system adapts to the mid power ban creating flow to an ever rising RPM. Exiting the single pipe we have our second pulse(Being that the single pipe is 5 inches shorter mid ban gases escape the single pipe faster)into the pulse chambers expanding by this time at a very rapid rate helping enhance high rpm. DG’s muffler pipe(being cone shaped)Creates a third pulse pulling the exhaust gases out for best top end. But god is it loud!!! (example take the spark arrestor out of your stock 400 and start it up)Hear comes the trade off. DG's exhaust system boasts a 6 hp gain And I don't doubt it. But it's god awful loud!!!!!! To control the sound start adding spark arrestor discs. But the more discs you add the more performance you cut, but the more quiet you become. Sucks doesn’t it. For me I like the DG longer head pipes for better bottom end. The DG shorter mid pipe for better mid ban But I have to go with DMC’s duel slip on for more flow and bigger surface area arrestor discs to control sound. Unfortunately DG will not sell the front pipe separately,(that’s where the R+D is)And I'll have to eat their muffler(what they call a muffler)In a nut shell the amount of length of the twin head pipes determines amount of bottom end torque. The length of the mid single pipe determines mid ban toque. And the size and length of the pulse chamber determines high RPM power flow. Then adding spark arester discs cuts noise but also performance Good luck keeping it quiet. Build your system to your needs.

 

Does that DG pipe add 6hp to your 430? Or did you mean it would add 6hp to a stock 400ex? 6hp seems like quite a gain to me. I can't believe there are no other 25" headpipe systems available!
phil

 

Philzie..430 is just a name I made up at the spur of the moment.DG claims 6hp on stock unit with no spark aresters and is loud as hell. As far as other different size head pipe manufactures haven't seen any yet,If you see some let me know.

 

I have a 400ex and I installed a headpipe and silencer from noleen called the HVO high velocity output.Have you ever heard of this pipe and the advantage to it. Thanks

 

I got the Big Gun Pipe and Headers on my 400EX. Its not to to loud and also give amazing power. Its a cross of quiet vs loud. I also just got my Rev kit from W.B. and am planning on installing it. I also have a new carb planned when I get the money

------------------
400EX LT250R Blaster

 

I recently got the Curtis Sparks exhaust for my 400EX. I also got the jet kit of course, and also the foam air filter Sparks has available. I am very happy with the whole kit. The filter came with a airboot reinforcing ring, and fits all together alot better than the stock unit. The two drawbacks to this exhaust is there is no spark arrestor and it is loud enough to wake the dead.

The good parts are it looks awesome, and improved the throttle response of the machine everywhere. I hit my rev limiter even more now than I did before. Luckily, I have ordered a rev kit from CT and should get it on monday. The whole package of the pipe, air filter and jet kit is great. I can upshift going up hills I used to have to lug the last bit of. I have not seen the Big Gun in action, but look forward to matching it up against my machine.

Adam Smith
99 400EX

 

Readrider.....boger....Adam.
How many inches are your header pipes?Mid pipe?

 

Hey Boger! I own a 400ex and was thinking of getting a rev kit from W.B. Just wondering if you got your's installed and if you think it's worth it. Do you notice a big increase in speed?

------------------

 

After I install a new exhaust and filter system, whats the proper way to rejet and how do I know if its really necessary? Is a plug reading accurate enough?

------------------
Steve Small, 00' 400ex, 00' 325 Trail Boss for the Mrs.

 

EXtreme
Sorry I took so long,But I was figuring out how to word this.Yes it is inperitive to keep a ballenced flow of air and fuel,If you change your exaust pressures you must rejet your carb to accomidate more flow.

Wach out for heat build up,Mine is being done right now by a good friend and certifided honda mecanic, Will update.