Building my own exhaust?

I've got an old gs500 that I've been playing around with and I'm currently in the
process of butchering the hell out of it. I've cut the tail end by about 14" and refit the plastic to shorten up the rear end. Removed the front and side fairings and mounted a new headlight, put flatter handle bars, swapped out the front end for an upside down front end off of a gsxr that a buddy had , mated an r6 rear shock out back and mounted up a small trail tech speedo and tach......


The aim of my little project was to make the bike feel small like it is. At 5'4" the bike looked and felt way too big with that long ass tail and front fairing. trying to keep the build cost down under $200 or so because , well to be honest it is after all just a little GS.

The only thing left is to do something with that big ass exhaust can. I've thought about building my own but don't really know anything about how to do the baffles and all that crap. I'm not worried about performance ( it is just a GS) and I know I'll have to re-jet and Prob go to a diff air filter so I don't damage the engine. I just want to make a really small muffler. Hopefully mount it under the bike. So........

Does anybody have any tips, suggestions or know of a decent web site that might have some tips or info?

 

http://coneengineering.com

 

Google Shervin.

-jim

 

I may not post much but I read this board about everday.

 

super trap

pick you up a small supertrapp the size you want. simple to add or remove discs to tune the sound and performance to what you want. I've made a couple for my old sr500's with good results . I had a local muffler shop bend the pipe for me .I used the stock collar. that was my solution. b bill and darethea

 

Thanks Pat, I'll take a look at that page when I get home from work.

 

this has lots of info on how four stroke exhaust systems work. warning: there's math involved.

http://www.amazon.com/Four-Stroke-Performance-Tuning-Graham-Bell/dp/0857331256

 

I hadn't thought of going that route Bill, I'll look in to it. I sorta got tunnel vision once I came up with the idea of building my own.

 

No worries. Reasonable prices there, if you find an end can from the scrap pile that site will have the pieces you need to make it all work. Or order a muffler from them too depending on your left over budget.

 

We just sold my wife's GS. I have a Haynes manual and some HH brake pads that I did not give the guy, Well because he was cheap and lowballing.

$35 for both if you are interested.


Have you searched GSTwins?

http://gstwins.com/gsboard/index.php?topic=66620.msg801576#msg801576

 

I've heard roof flashing is the material of choice for aftermarket DIY exhaust builders. Roof flashing and pop rivets.

 

Can you weld?

Specifically, can you TIG weld and are you set up with a secondary line for your Argon to purge the backside while doing stainless? Do you have a metal cutting bandsaw and are you skilled enough to use it resulting in the kind of joint fit-up that the TIG process requires? Have you figured out what the primary diameter should be, and what it should step to, and when?

Exhaust building is 80% math and 20% style... at least for efficient, well functioning systems.

Not trying to be a dick, but if the answers to all of the above were yes I doubt you would be asking. Can you make something to get you down to the local Starshumcks without it falling off.... maybe. But it's likely not something you're going to be happy with long term.

Sometimes it's best to hire things out. Maybe not, that's up to you.

 

Well to answer your questions.......

Yes I can weld. Been machining and welding for damn near 30 years. Everything from purely old gear cutting and die making to running my own shop doing prototype work for various aerospace and automation customers......

As far as machining and building or more importantly designing something for a exhaust for an internal combustion ??? Well no I have no idea on how to go about building one that will sufficiently handle the job of back pressure and tuning.....yes I can build one that won't fall apart but it may not actually work very well. Thus why I asked if anybody had any ideas, tips or websites.

 

Just looked at that site. Believe it or not I think my girlfriend has that book in her garage. Her grandfather passed away about 7yrs ago and left her all kinds of motorcycle related stuff along with about 10-15 BSAs and a few Nortons and loads of parts, everything from frames , gas tanks to engine cases and electric for them. It's all just sitting in her garage waiting on her son to get old enough to tinker with it all.

 

??

Then you should have no problem for the application you asked about. Making a halfway decent 4 stroke exhaust system is not rocket science for someone of your background, especially for a mild parallel twin. (not to say there are not significant gains realized by some established exhaust manufacturers). Buy some SS mandrel bends, start at a stock-ish ID near the head and step it up .065" ID or so a few inches from the exhaust port, and fit a functional muffler of suitable inlet diameter and machine/weld up a hanger or other fixture to secure it. For a non performance application you should be more than capable. It's not like you're making custom chambers for a TZ250.

 

Like Bill said...Supertrapp in place of the muffler works. I didn't notice any change in performance vs. a Kerker megaphone with this setup.

 

That's the kind of set up I'm looking for. Thanks,that gives me something to at least compare to

 

Slow cone taper from proper primary header length think this one went from 1.5" header to 3" glass packed perf-core before the supertrap cap. The meg and an FCR-MX pumper completely transformed the bike from dull torque to a lively wheelie beast.

 

very cool site

 

On my GS450 we cut the collector off of a Kerker that was on it and welded a mid-pipe from a ~2002 GSXR in place. That allowed me to bolt any muffler that fits the gsxr on it.