Anybody else running one?

pak39

pak39

New Member
After playing around with some exhaust configurations I've come to the conclusion, so far, that a straight pipe is gonna work best for me.
Is there anyone else that runs one and rides their bike every day? I know it is really loud, but it sounds so sweet and it gives me that low down torque I need to climb the hills around here.
I did build an expansion chamber that gave the motor a nice power band at the top end, about 8200 RPM, but I didn't know it would take away almost all of the low end power. It was the first proper expansion chamber I designed and built so it was a learning experience. Maybe one day I will try to build another one that moves the power band much lower.



I used 1" O.D. tubing from Tractor Supply.
 
That has to be ear splitting loud. I can't imagine how many people you must piss off every day. I'm just sayin'...
I'm using a low cost off the shelf banana style expansion chamber (with silencer) and pieces of old handlebars for pipe. It took some hacking whacking and welding, but I tuned the pipe to that sweet spot. I'm just sayin'...
 
I made a megaphone pipe for a race bike. ripping up and down my neighborhood tuning the bike didn't make any of my neighbors happy, and it was by far the loudest bike at the travk.

I have a decible meter app on my phone that goes to 100db and it maxed it out. it would be illegal for motocross racing, which i think is 89db max, and it's illegal according to CA street bike laws.

I thought it was kinda cool though... :)
 
A properly constructed muffler will make little difference to your low down grunt.
I agree you must piss a few people off with that pipe.
My expansion chamber took away a lot of low down torque also, but...
As did my shorter inlet, and bigger carb.
Maybe a longer inlet tube and smaller carb if you want low down?
 
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No more needs to be said really.
 
This is what I'm running now........essentially a straight pipe with a 3/4" riding mower muffler with a steel pot scrubber stuffed in the end. Works great and isn't as loud as my expansion chamber. I had to drill some holes in the end of the muffler outlet to use a 'keeper wire' to prevent the pressure from spitting out the pot scrubber.

Good luck!!


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I believe I'm gonna start designing another expansion chamber to help bring the noise down. It does sound awesome, but it's getting a little old. Also, I haven't seen any cops while riding around like this.
 
Think short and fat for low end, long and skinny for high rpm when building a pipe.
You can also tune where the power hits by changing the length of the headpipe (the bit from the port to the start of the cone)
And running without a muffler is very annoying to EVERYONE except you.
 
Last edited:
maniac57 said:
Think short and fat for low end, long and skinny for high rpm when building a pipe.
You can also tune where the power hits by changing the length of the headpipe (the bit from the port to the start of the cone)
And running without a muffler is very annoying to EVERYONE except you.
Click to expand...

A longer header pipe is better for low end power, & a shorter one is better for high RPM power. ;)
 
Yup. Like Norm says, the header is just the opposite of the chamber. Longer for low end, shorter for more high end power.
I meant the actual chamber shape.
 
So I've started to design a new expansion chamber using Dragonfly75's excel file. Has anyone else used his file? This will be my second time to use it to build a pipe and it can be a little tedious but I believe he did a good job setting up the file.
 
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