I drilled the holes in the muffler like Pam said about 2 mounths ago. I have run mine with holes an it is just as fast as any of them. If you have not done any engine work, just drill the holes and save over $200 to spend someplace else. A friend of mine did it last weekend after he lost his WB, and he said that it ran faster with the drilled holes.

Many 250r's
87 250x
99 400ex

 

Can you post again (or point me exactly) how to do this drill work to my 99 400ex? Thanks!

 

On a 99 unbolt the plate on the end of the muffler. You will see a long piece of tubing with a screen at the end (I think that is the spark arrester). Near the large disc on the inside, I drilled 3/8 " holes around this tubing. Don't drill to many or the tube will break from vibration or ?. I think you have to do something different on the 2000's, beacuse it is made different. Pam said that all of the aftermarket pipe's give only and 8% increace in power. Depending on how many and the size of the holes, you can get a 4 to 8% increase in power. Has any one else done this and what was your results?

many 250r's
87250x
99 400ex

 

How much loader was the stock pipe after the mod?

Has anyone attempted this on a 2000 model?

How is it different than what he has described?

 

I think I will add that an aftermarket system will also be lighter in weight than your stock system. The stock pipe and silencer are pretty heavy and also restrictive. spend the money and put an aftermarket on. I do not have one on mine yet, but until they start putting polished aluminum canisters and head pipes on stock quads I will always be looking.


woodrider400. Stock 400ex.......for now......

 

I haven't seen an end cap off of a 99 400EX, but on my 2000 the restrictor is part of the housing and the spark arrestor is welded over top of it. I had a friend who has welding equipment grind off the welds that hold on the arrestor, cut off the 3-4 inch restrictor (leaving about an inch of material near the end piece), and then reweld the arrestor onto the end cap. It's louder than stock...maybe 3-5 db's...but sounds meatier and a little more responsive. In the long run it was a cheap mod, but I'm still gonna go with an aftermarket system, but can't decide on which one to buy. I'd really like to hear a few 400EX's with different systems before spending $200-500!

 

Hey all you guys out there, has anyone heard about the T6 Procurcuit pipe yet. All I know is that they offer the slip on and the complete system. Any help is appreciated.

 

Go here GT Thunder and see for yourself. They have the dyno test results to prove what you're looking for. #1 came in with the DMC full race, #2 with the full race E-series, big gun and supertrap were low on the list. Check it out...it's worth the look. I currently run a megamax slip-on and am covinced enough to change to the full e-series to get the extra punch that I'm looking for without tearing into the engine.

 

By the way, my friend just got the powercore IV2. It is louder than *#%@ compared to stock. It isn't quite as loud as a WB E series, but it is way louder than stock. We called and complained and they said that they tested it on the yz400 dirtbike vs stock, not the 400ex. Gee, there is a no brainer, the yz400 stock is way loud, not a Honda. I am now interested in the YOSHIMURA since they are all loud. At least my quad will be on a diet with titanium.

 

Has anybody used the FMF Powercore IV-squared with the Powerbomb head pipe yet ? If so,how's the performance ?