KymcoForum.com
Scooters - 50cc => Agility 50 => Topic started by: davidwheaty on January 14, 2013, 05:25:44 PM
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hi, im getting a new exhaust made for me, luckily my cousin makes car exhausts for a company and can knock me up an exhaust to my liking in his lunch brake ;)
the question is, is there a specific specification for greater performance increase? i.e. down pipe thickness, muffler length width etc...
any help is appreciated :)
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You actually want the pipe to be bigger than the exhaust outlet, a step there stops backflow. Then the length,
it should be tuned to the RPM's you want to enhance. Usually the head pipe is too short on a scooter as it looks
correct. I have a chart for intake, I wonder if it is the same as for exhaust?
As you see 18" has a maximum amplitude at 8000 RPM's on the second harmonic. This can increase power
by 10% if properly sized. You could tune for the 2nd and 3rd to occur at the torque peak and HP peak...
(http://i1061.photobucket.com/albums/t478/MotoRandy123/Holder/intake_tuning_lengths_chart_477.jpg)
You also want to step open at the muffler to tune to different RPM's. Here's a properly setup pipe;
(http://i1061.photobucket.com/albums/t478/MotoRandy123/Holder/MFactoryYagerMuffler.jpg)
And the Dyno chart;
(http://i1061.photobucket.com/albums/t478/MotoRandy123/Holder/MFactoryDyno.jpg)
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...moto, you got good specs...
:o
..where were you a cpl years ago...
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Messing with the big bikes back then. I love making things work better!
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..i learned to tune by ear and eyes......
..the specs bring all that home...
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Never learned by ear so gotta use them charts! (When I can find 'em)
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Messing with the big bikes back then. I love making things work better!
what happened to the big bikes randy?
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Well I've always been big on the smallest that does the job is best but the economic
down turn pushed me this time to loose the big(ger) bike and get back on a scooter.
I've always enjoyed wrenching as much as riding so usually I get a bike and fix all it's
flaws then get bored with it and move on...