YES, it makes a difference

by (Login themopedwhiz)
Moped Gurus

with 2 stroke engines, the carb flow and jetting has to be matched too the 'thru put'..

when an exhaust is made less restrictive ( removing baffles ) cutting pipe's etc..

more air is allowed / forced to move thru the engine..

depending on the carb opening, the air filter box, and the main jet..

the fuel mix either gets leaner or richer..
often you expect one thing and the opposite happens

it's a fuction of velocity ( air speed ) Vs volume..

more air without a speed change makes the mix lean and the jet will need to be bigger ( if you keep things that way )

faster air velocity means the air will draw more fuel thru the jet , making a richer mix..

tuned exhaust are designed to force a back pressure resonance way at specfic RPM ranges which acts to charge the cylinder/combustion chamber with more fuel mix

you said you are running rich and dropped the needle all the way down..

as a test... try this..

remove the airbox and foam filter..

and warm up the engine ( stay out of the dirt )

if you can adjust the carb so it runs better then you will need a less restrictive filter,

other wise you will need to change the exhaust or goto a smaller jet..
but samller jet means less fuel and less speed..which is why you moded the muffler to begin with..

also did you try bypassing/disconnecting the autochoke

Posted on Feb 16, 2004, 8:30 PM
from IP address 151.144.164.94

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