All credit for this article belongs to Crazie. The link to the original thread is here.
People asked for it to be re-written to make it easier to see the results and since I was bored, here it is. I tried to write it in a interview Q&A kind of format. I had it all wrote up nice with the quote boxes but an error message came up saying I had quoted too many sources, so i had to get rid of that format and just write who wrote it. Sorry. PM me if i made any mistakes on it or anything. Also, let's try not to spam this one up like the original one



HOW LOUD IS IT, AND WHAT IS YOUR JETTING?
Crazie
As for the sound. It's a lot louder than stock...but not overkill. It's still not as loud as a couple of people I ride with. We rode it around, but didn't have a chance to really open it up. I think it sounds really good. Not overly loud to me. Has a nice deep rumble when it idles. The thin metal welded up fine. My friend's brother did all the welding.
As far as jetting goes, I'm at 5,000ft and was running a 155 with just the pea-shooter cut out. I may have to go up a size...but I was running a bit rich before the conversion. The air is a lot thinner at this elevation....so I may not run as big of a jet as most people anyways.



WHAT TOOLS DID YOU USE?
Merriman
What tools didn't we use.....
after removing the pipe, it needs to be cut in 3 places. They (since I didn't really work on it, only offered my "expert" advise on the situation) cut it with a grinder, and cut-off wheel, but then got smart and used our plasma cutter. First (if you want it short) cut it right behind the bolt mounts for the end cap, cause you'll need this later to weld to the end. Then cut it right in front of the last mounting hole (this way it will still bolt up in both locations with out having to relocate the mounts) The 3rd cut is at the begginning of the silencer on the first weld. Once you have that completed, it's time to break out the BFH (Big F__king Hammer), a chisel, and a large punch so you can beat out the innards. They also took a drill, and drilled out the chamber walls punching little holes over lapping each other all the way around until it was loose and able to come out. They did this so there wouldn't be as much pressure pushing out on the silencer, making it easier to punch out. After you gut the silencer, sit down and take a break, cause by this time your ready pass out. Once break time is complete you'll need to smooth all the edges of the silencer that you hacked apart and prepare it to be welded back together. You'll need some mesh screen to role up for a make shift-pipe for the now free flowing straight exhaust. Wrap the silencer packing around the outside of the mesh wire, and set it aside. Take your now hollowed silencer tube (the main body) and "tack-weld" it back to the smaller begginning piece where the pipe meets up with the silencer. once you tack it, put it back on the bike to make sure it fits before you completely weld it. After you get it to fit, weld it up, cool down the weld (stick it in water) and put the mesh tube with packing wrap inside the silencer. Take the small nose peice with the bolt flanges and line it up on the silencer (make sure your nose cap will face down, otherwise you'll look plain silly) and weld it in place. Next put the end cap on, stick it on the bike, and fire it up, because you are deffinitly to anxious to know how it sounds before you finsh the job. After you hear it and w00ter off the neighbors for a little while take the pipe back off, and grind down the welds so it doesn't look like a$$. paint it up, and put it back on. You should be complete.
Tools used..
Plasma cutter.
Grinder
Hammer (BIG)
punches, and chisels
Welder
Sander
Paint can w/ paint
That's all I can think of right now.



HOW MUCH LOW END DID YOU GET?
Crazie
Yes, I compared it to my stock silencer and I used the one with just the pea-shooter cut out to make this one...way more low end than both. I'm not even going to buy an aftermarket now. I've ridden a z with the same setup as mine, but with a full yosh...I think it's really close on low end. But I'll know for sure when I ride both of them on Friday night.

COULD I DO THIS WITHOUT A WELDER?
Crazie
You could do it without welding, but it may be difficult. I would say maybe get a sleeve that will fit around the pipe and then maybe use pop rivets and a high-temp sealant under the sleeve. If you know anyone with a welder....it may be easier though.


THE EXPANDED METAL I PUT IN GOT BLOWN OUT AFTER A WHILE?
parker_066
I did that on a Scrambler i had, and I seemed to have problems with the mesh collapsing and ruining the packing. I even tried to use three layers of that stuff but it still did it. So what i ended up using was the core from a cherry bomb exhaust like you would use on you truck. Cut it to size and never had that problem again. Just my 2 cents for any one who may try it. It is way better than spending all that money for a shiney aluminum canister.


WHERE CAN I BUY THE EXPANDED METAL?
Crazie
You can find some at Home Depot....or probably and home improvement type of store.

CAN YOU DO THIS TO AN AFTERMARKET EXHAUST?
Crazie
Several people have done this mod with an aftermarket exhaust, but I'd ask some questions about performance issues if I were you. There is a guy on this site that offers and exhaust cutting service for aftermarket pipes. I'm just not sure if the results will be the same with an aftermarket pipe.


WHO ELSE HAS TRIED THIS?
RAGE
I actually bought a stock can and modified it just like Crazie describes.

The mod did several things for me.
1. It woke the Z up on the bottom end. Does it have more torque? The better question I have is, Do I really care? If I can grab and go and I get a better response from that throttle then I did with the old can then you are damn right something is working.

2. It flat out sounds better. No more of this coughing thru a tin can sound. Now it barks thru a pipe.

3. It kept my wallet nice and fat. Truthfully if you don't want to do the mod I have nothing against you or anyone else who thinks it bogus. I felt about the same way, I wasn't sure what it would do, so I bought an extra can and tried it out. If it failed miserably then I was out $25 total.

BUT.. If it works as I feel it did for me for the time being then I save myself about $250 and at the time almost $325. Cause back then very were very few pipes out.


IS THERE ANYTHING SIMPLER I COULD DO?
tlronny
i just scored my '05 and couldnt afford a slip on so I modified my stock muffler instead.




By using a 1 3/8" holesaw on an extension bit I drilled through the exhaust wall that you can see if you look down the rear of the pipe (after removing the spark arrestor).
I also made the endcap at work so it really cost me zip !
The airbox lid got 9 1/4" holes drilled in it for a slight increase in airflow too.
I live at sea level and have not rejetted but it runs fine for me and is a lot louder than stock.
The power seems to come on quicker and it hits the rev limiter much easier but I dont know if its got more HP or not.

;)


A LITTLE OFF TOPIC, BUT DO THOSE ENDCAPS ON EBAY WORK SIMILARLY?
PeeWee
I hate to break it to ya but all you gained is sound...there is no performance advantage in that. Look in the faq section...for less than $11 you could have gained 5 times what that will give you. The 10-15% increase in power comes from the jetting and opened up air box alone...i'll bet a dollar to a donut that if you dyno it....you'll be lucky to see a .1% increase in the cap alone. Matter of fact....you could have done your stock end cap the same way and saved money!!!! I'm not trying to be an ass...i just hate seeing people get screwed over!!!


WILL RUNNING THE EXHAUST WITHOUT THE SPARK ARRESTOR DAMAGE THE MOTOR DUE TO LESS BACK PRESSURE?
Crazie
Not at all. Take a look at most aftermarket silencers....they're nothing more than a glass-packed (fiberglass) muffler with a perforated steel sleeve going all the way through. You can see straight through most of them.


DID CHUCK THINK OF AN EVEN SMARTER WAY OF DOING THIS?
Yes, lol.
CFM-Z440
I have some helpful tips that i stumbled onto while building mine

I bought a 2" automotive glas pack(red ones in the barrel at napa) and cut the core out of that. It fits perfectly!!!
Also I used a snomobile drive shaft bearing plate to make the core fit @ the back of the silencer! Way too convienient. the core fit it perfectly after some light grinding, and the plate fit in the silencer end just as good!

The only other thing i did different was I left mine the stock length. I just beat the baffels out after i cut both ends off, instead of cutting the mid section out (hard work but can be done)

I am Thrilled with the sound.
Its real deep, and it actually idles pretty quiet!

I cant thank you enough for this post I would not have tried with out it!

Update
Just rode it after a guess at jetting

I had plenty of mods before i tried this check sig

I am verry happy I noticed an over all increase in power!
I was supprised to find that my biggest gain seemed to be at high rpm
But i was severly restricted before considering all the mods
Im so happy with it that Im not going to buy a pipe now
I can save my money for a cdi box instead


HOW DID THAT WORK FOR YOU?
CFM-Z440
Update#2

Had mine on a dyno at little sahara power sports.

Found an additional 2 hp by taking my end cap off.(Stock cap completely gutted)
Also had to go up 2 dyno jet main sizes to do this
As i posted before I left mine stock length. But I think Im gonna cut it down.
I have a theory that I will maintain top end hp longer.

I will update again after I do it, but I only have the seat dyno now.

I pulled 30ftlb of tq @ 5000 rpm
and 34.77 hp @ 6500 rpm

I think the intake hot cam was to blame for the lack of top end more than the pipe.
The thing has a ton of low end to mid, but thats all it has.

(I have found out since that time that my intake cam had been adjusted before I bought it and was not correctly timed. That was the big reason that the numbers came out funky)



HOW CAN I MAKE THE STOCK EXHAUST LOOK NICER LIKE AN AFTERMARKET ONE?
saintb6969
Crazie,
Hey I am new to the forum, but I read what you did with your exhaust pipe and decide to give it a shot. I modified your design to where the only thing I saved from the old exhaust was the ends. I used a 15" piece of 3" stainless steel pipe, welded a inverted stainless steel cone inside the inlet side, then I took the center mesh core out of the center of a 2" Cherry bomb glass pipe welded it to the end of the cone and to a end plate at the outward end (after I put the packing in). Then I took the end cap cut out of the old center pipe and welded in a 2" stainless steel pipe running it flush to the end cap nozzle (must take the nozzle off inorder to remove the old pipe, then weld it back on) I cut my old mounting brackets off the stock exhaust and welded them onto the new and after alittle polishing of the stainless steel pipe I mounted it and was blown away at the sound it had when I fired it up (AWESOME!!!) it sounded like a race car, but not to loud though PERFECT! Then I took it for a test ride and it just blew me away at the difference, before inorder to get a 2nd gear willie I would need to rev then pop clutch, now it is just hit throttle and the front end comes right up. So far this is the only mod I have done but I use to buil race car engines for people and I have almost every tool I need and I am to cheap to pay the outrageous prices they want for most mods I can build my self. I will post any other new mods I develope inorder to help my fellow ATVr's to save some dough. As for the exhaust pipe I have pic's and instruction drawing but can not figure out how to post them any help. Sp far I have not rejetted the carb yet, really don't think it needs it yet I am after the air box next!!!!!!!!!!!!!!!!!!!
Oh yea all together this exhaust build cost me $20.00
07 LTZ 400
MODS: MINE exhaust built by me!

Good deal, man - damn good job condensing everything. I moved this to the FAQ Section - it's worthy enough to be in there with the original article, for sure.

I'm going to lock the topic so it doesn't get cluttered up with a bunch of BS. Anyone that wants to ask a question about this process, then go into the "Performance Section" and make a question thread about it, and link this article into your new thread there. Easy.