Project GS550L Supermoto street fighter

[hardlydangerous]

A few months ago my freind found a great deal on a awesome shape 84 GS550L.
Sometime in Nov he crashed it pretty hard totalling the lights, gauges and brackets, controls, cables and fuel tank.
Frame wise the bike is ok,
So that has us re-building the bike on a very limited budget... hello street fighter. The bike STOCK is very light and a wheelie machine, with the weight reduction this should be a mean lil bike.
ill post the progress...

So far we ditched the guages, lights, brackets, center stand, dual exhaust, front fender, and some wiring etc

Plans are to put on a CRB, R6-1 or GSXR tail section, and dirtbike front fender and headlight

I'm currently building a 4-1 header and exhaust system, most likely a Hindle pipe.

[Slofuze]

This might be interesting! Keep us posted!

[H-2 CHARLIE]

Did you wash it down with mud and a baseball bat ..?

[Waltari]

Sounds like a fun project. I've often thought about doing a cafe out of a 550e. Keep us posted!

[zcphoto]

you're off to a good start.

[hardlydangerous]

Did you wash it down with mud and a baseball bat ..?

Pretty much
He flipped it riding down a mud/gravel road in a bad rain storm.

[thedike]

Shame, it was a nice looking bike.

[Trackerrrr]

Pretty much
He flipped it riding down a mud/gravel road in a bad rain storm.

And what possessed him to do such a bright thing?

[VifferJim]

The 550L was my first privately owned motorcycle - identical to the first pic you have posted (first bike was Army issue). I'm enjoying seeing what you're going to do with it.

[hardlydangerous]

And what possessed him to do such a bright thing?

He's just a kid, doing dumb kid things.
We all ride down the odd dirt road, but he never realized the 2nd half of the road was a clay road, and after a rain storm its going to be slick as snot.
until it was to late that is

the 4-1 header is complete, ill get some pics tomorrow, what a monstered of a nightmare they are with out a pipe bender. Up to 10 cuts in evey pipe just to make the bends smooth and allow me to shape them and still get at the filter, and drain plug.

[hardlydangerous]

Well the exhaust is done. Huge welds were needed due to the dual wall header pipes and paper thin outter pipe. Both the inner and outter have to be welded to prevent them from breaking inside and rattling.
This is just rough for now, Ill grind the welds a bit before its painted.
The pipe was a strait pipe with a drill end cap. I closed it up and welded up the holes on the outside of the pipe and it sound nice and deep. I still have a very slight header leak on #1 cyl, but new gaskets will fix that.



Hers a couple vids of the pipe before and after the muffler baffles were welded up

[ame]http://www.youtube.com/watch?v=TS4UFldHDks[/ame]

[ame]http://www.youtube.com/watch?v=jQvJquhdJ3I[/ame]

[loudnlow7484]

I think it sounds fantastic. What kind of baffles did you put in there?

I wonder if it wouldn't have been easier to start off with a different header. Either way, sounds good!

[hardlydangerous]

Easier yes...
But buiying a header for a GS550E is hard enough let alone the cost.
The owner is a student so funds are liminted, building the header and collector is easy, just time consuming. Plus he got a great lesson in scratch building an exhaust system to custom fit, as well as how to tune it for the sound.


Its just a standard 1.75" strait baffle. I did not glass pack it, it don,t really need it.
I may go up to a 2" baffle. the shorter and larger the baffle the deeper tone you get.
We planned on fitting a hindle pipe on here but decided this will do for now.

Today we are cutting down the seat, and building a tail for it. I like the MT-01 look without the pipes

[loudnlow7484]

a 1.75" baffle like this? http://cgi.ebay.com/ebaymotors/1-75-...Q5fAccessories

If that's the case, I might just keep my cut-off midpipe yet! I was thinking I would put a muffler on it, because it sounded too raspy, but if that little baffle will make it sound like your project, I'll keep it!

Can't wait to see what you end up with for the tailsection.

[hardlydangerous]

There is a lot to a performance exhaust if you want both sound and performance.
an open pipe dumped off is not one of them.

That louvered baffle is a BAD design for this application. It’s all about AIR SPEED and resonating affects. In order to increase air flow you need to do two things, keep the exhaust gasses HOT and reduce turbulence that can cause sound waves to bounce around and create back pressure. Turbulence caused by rebounding sound waves inside the exhaust can be worse than a smaller baffle. However colliding sound waves cancel each other out and make the exhaust quieter. If you pull away too much heat from the exhaust as it goes through the baffles it will cool the exhaust flow and slow it down increasing back pressure. A strait perforated baffle like pictured below is a far better design. After all there is already enough backpressure cased by the 4-1 collector, the pipe should be as open as possible with as little restriction, but still muffle the sound.
The one you pictured is designed for a drag pipe without a muffler such a Harley pipe or cruiser (for a single cylinder application) meaning 1 pipe per cylinder. Start shoving 4 cylinders at 10,000rpm into that and your going to lose useable power

The strait perforated baffle design reduces high frequency sound waves better and gives you a lower tone, a Louvered baffle does not and makes the pipe very raspy.
I pipes inner and outer shape and design and length also plays a large role. A mega phone pipe is designed to enhance low frequency sounds. A larger, shorter can with larger inner baffle diameter will give the bike that LOW deep tone.

That’s why the D&D and Yoshi pipes are raspy and higher pitched and produce less HP then a pipe like the Hindle or two bros.
For instance the two Kats I have in my shop
Yoshi is 18” long has a 2” inlet 1.75” baffle and 2” outlet
Hindle is 16” long 2” inlet 2.25” baffle and 2” outlet.
The larger inner volume, and diameter and the perforated strait tube baffle will absorb more hi frequency sound waves then the smaller longer pipe. Also the smaller restriction baffle creates a restriction and deflects sound waves that collide with each other.

I used to work for MBRP when there shop was in Emsdale Ontario building custom exhausts, expansion chambers and silencers.