After market cans?

[Motu]

KK,
Good,you do know some exhaust theory.Yep,300 ft per sec at max rpm is a good guideline,this is acheived with diameter of the pipe,if the pipe is too fat,gas speed goes down and power suffers everywhere,need more back pressure they say.Too small and top end suffers,but you pick up bottom end,typical factory pipe.Length of pipes is resonance tuning and is how old farts like me muck around with exhaust systems,there are formulas available anywhere,nice and easy on singles.

[riffer]

I'd like to rip out the baffles out of my fzr pipe, and it's too damn quiet and restrictive as hell.

I know fizzerman (WT's brother) has done it to his but he's hardly ever on kb. Does anyone know how to rip out the baffles on my fizzer with the original zorst on?

I guess it involves hacksawing the back off the zorst and pulling out the baffles. Then do you replace them with who-knows-what, and weld the back on to it again?

Anyone have a cost-neutral solution? I'd rather spend time than money on it, especially after spending the better part of $900 on the bike in the last month (money which, incidentally the CDFO insists we didn't actually have to start with).

I have all the tools except the welding gear which I guess I could borrow, beg or steal...

[vifferman]

I'd like to rip out the baffles out of my fzr pipe, and it's too damn quiet and restrictive as hell.

I know fizzerman (WT's brother) has done it to his but he's hardly ever on kb. Does anyone know how to rip out the baffles on my fizzer with the original zorst on?

No, but ignorance never stopped me from pretending I knew stuff...
On my VFR, I too wanted more sound but had no financial madate to purchase anything. I sussed out the internals using a torch, then drilled a big hole through the main baffle using a large drill bit on a flexible shaft, then followed up with a coarse round bastard and a long wooden handle. Then instead of the gases coming up a pipe, being deflected off to the side of the first baffle, up the muffler, down the muffler, then up the muffler through the outlet, they mostly just went up the header pipe, through the hole, and out the outlet. It sounded OK, not as good as an aftermarket can, but deeper and raspier than stock. Of course, all this work had to be carried out after Mrs FS was asleep, as she strictly forbade me from "sabotaging the muffler" after one of the cans on my VF500 rusted out and I had to have some s/steel cans made by M/C Exhaust Specialists in Chch: their brief was "make it a bit less wussy". And it was very good too! Anyhoo - I digress. The hole that mysteriously appeared in my VFR's muffler made it run a bit leaner (less back pressure), which was very easily fixed by shimming the carb needles.
On the VTR, the pipes were vandalised by a previous owner, presumably by using a hole saw the diameter of the inside of the end caps (see http://www.burniemorgan.com/motorcyc...ml#bafflectomy)
I had plugs made to restore it to stock-looking mode (see http://community.webshots.com/album/88297322swwFNk) and my original plan to rivet or bolt these in wouldn't work, as they were about 1mm or so too small a diameter, so I stuck 'em in using high-temp silicon. Worked a treat, and makes them easy to remove too.

[Two Smoker]

Well my baffles "accidently" fell out........ But ive got an Arrow can hooked up for the RG at Colemans hehehe.....

[riffer]

OKay, I had a look at the bafflectomy. I'm a bit concerned that it might be a bit loud after that.
What potential difference is there to the sound if you pull out the whole baffle?

Do I need to put in a new pipe after taking out the whole baffle, or can you just leave it open like that?

Considering possibility of failing WOF here....

[riffer]

I'm also looking at getting a two brothers pipe cheap. Is that a better option, even if I have to weld it on to the old header pipe?

[vifferman]

You'll definitely fail the WOF with a bafflectomy, and you'll probably have to do some retuning whatever option you pursue. The 2-Bros may be a good idea, but even that may fail the WOF at some places.
The thing is, apart from styling, materials, quality of construction, there's stuff all difference in general principle between aftermarket pipes. All of them basically have the same sort of perforated core, with muffling around that. Back-pressure is generally taken care of by a reduction in internal diameter at about the place where the first baffle (or kink in the muffler, in some cases) is in the OEM muffler. This helps to reflect the pressure wave back towards the zorst port.
The OEM ones generally have some system involving tubes and baffles, so the gases have to take a circuitous journey from header to outlet, often going back and forth a few times.

[Kwaka-Kid]

KK,
Good,you do know some exhaust theory.Yep,300 ft per sec at max rpm is a good guideline,this is acheived with diameter of the pipe,if the pipe is too fat,gas speed goes down and power suffers everywhere,need more back pressure they say.Too small and top end suffers,but you pick up bottom end,typical factory pipe.Length of pipes is resonance tuning and is how old farts like me muck around with exhaust systems,there are formulas available anywhere,nice and easy on singles.

hmm, ive been trying to learn as much as poss as far as exhausts go but man it gets way outta hand sometimes and there are ppl with differing opinions! But i get what your saying exactly!, so its all about moving the peak power etc and where u want the power. Yeah my old man was a bit of an exhausts man way back when - and said the singles were great - he loved tweaking around with different mufflers/systems as it was easier then having 4 cyls to balance.

My one question that still stands to anyone that knows something about exhausts etc is exactly WHAT will happen if i take my exhaust off all together etc and run around like that? aside from it being very noisey etc and affecting power, what is the detrimental effect against the engine? so far nobody has ever answerd it aside from my old man saying you burn valves, but i just love to hear other opinions or even one to confirm this, nobody knows damnit!

[Milky]

I'd also like to know if it really matters what the internals of the pipe are... ie can I just weld a perforated plate onto the back end of the exhaust pipe, or will that create some weird resonance stuff and destroy the power curve? In essence, how forceful can you be with muffler/header etc mods before it has a noticable effect on the performance?

[Motu]

That brings back a funny memory KK - back when we used to drive around in crap cars we picked up for next to nothing...my mate reckoned that when your exhaust flange blew out it would stuff the motor real quick,and he was right...every car he had that blew a flange gasket was soon totaly stuffed - but I reckoned the flange gasket was only the first thing to crap out,the motor was going to go no matter what.Step on a cats tail causes brake failure.

Milky - rough and readies ok,a butchered job can be spot on,done by the book a total stuff up.With resonances if they are all higeldy pigeldy no worries,when it all lines up it can kill power or give a good boost.Change direction 3 times,cheap,easy,and it works - like turn it around,then back again,oh that's twice,but you know what I mean,car mufflers are still done like that.

[Kwaka-Kid]

yeah motu thats the way my old man used to design his! but it could go thru quite a number of back and forths and hed have changable 1 bolt baffles to try out different exit holes and styles.
Interesting though... Lack of backpressure hmmm, stil ldoesnt answer my question though does it motu? only contributes to the need of a straight answer!
hmm, milky what you could experiment with too is just the exit hole size using a washer, or you put it usually ahead of the muffler not at the very tail end, i exp with the CB250 like that as it had a straight out megafone, but a washer midway in the zaust seemed to help alot in terms of power where i mostly used it (down low and midrange)

[Motu]

Ok,to answer the question - no,I don't think so,check out aircraft - WWII Spitfires for example,they had very short header pipes,straight off the head,the exhaust gases have more energy that way and actualy improved thrust,kinda jet powered like.Working with resonance tuning the figures give very short header pipes,you just double the length to fit a bike.Check out a dragster from the 60s,very short header pipes,say about 12inches long - double that and you got a bike header pipe.It's also about disapating energy,when the gases turn in a muffler they also expand in a chamber,then get put down a pipe again,then another expansion and into a smaller pipe,less energy at each turn.

Actualy the guys who make aftermarket exhaust systems are being tricky and playing with our minds - your bike now sounds nice and makes more power - obvious eh.No...we have two totaly different things going down our exhaust pipe - the hot exhaust gases themselves,that's what we want to travel at 300 ft per sec.The other thing is the sound - a sonic energy pulse traveling at around the speed of sound,they are not really connected at all,but it's hard to seperate them in our mind.Tuning an exhaust system is complicated and the finishing touch is the most important - making it sound nice.These days that means taking out the high frequency noise to give a nice deep throated throb,it could sound like a Vespa or a Ferrari,it doesn't matter really - but it does to the customer!

The mufflers on my XLV750 are different from anything else you'll see around - inside the exhaust flows over helmholtz (sp?) chambers,these can be tuned to take out certain frequencies,next time I make some I'll try and make them tunable from the outside,then we can have fun at parties.Being a supposed desert racer I have picked on camel fart as my desired sound,well...I kinda like it....

[wkid_one]

Supertrapp mufflers are an example of ones where you can actively tune the pipe to suit the application.

[geoffm]

.Tuning an exhaust system is complicated and the finishing touch is the most important - making it sound nice.These days that means taking out the high frequency noise to give a nice deep throated throb,it could sound like a Vespa or a Ferrari,it doesn't matter really - but it does to the customer!

The mufflers on my XLV750 are different from anything else you'll see around - inside the exhaust flows over helmholtz (sp?) chambers,these can be tuned to take out certain frequencies,next time I make some I'll try and make them tunable from the outside,then we can have fun at parties.Being a supposed desert racer I have picked on camel fart as my desired sound,well...I kinda like it....

For those who want to get tek-er-nical, there is a program called "silencer" which will give you the sound output through the octaves of different sized exhaust chambers given an input spectrum, so you can tune the chamber size to clip certain frequencies. Free too
There is also a program that will give you the octave sound power levels via a mike and soundcard. Can't remember the name of it right now...
Geoff

[moko]

I always keep mine stock these days.Or at least legal,too much hassle at M.O.T. time(same as W.O.F.) for a start as tampered with or replacement exhaust without the right stamp on is an instant fail.Plus now I`m older and debatably wiser I reckon the less noise you make the more you get away with.My Fazer gives out a really neat low growl at high speed and I can razz along at any speed I want without attracting loads of attention while there are plenty of guys around with full-race systems that you can hear coming for ages before they arrive,talk about asking for trouble.Also it`s pretty selfish,just finished work and got home at 3a.m.,dont think my neighbours would appreciate my Yams acoustic qualities if I woke them all up at that time,there used to be some wanker on a big V-twin of some kind that used to regularly shoot through here at 2a.m.-ish at the weekend,sounded like Armageddon,I`m a biker and the prat pissed me off let alone "civilians",this is a built up area and he didn`t do a whole lot for the image of bikers amongst the general population