auto zone air filter mod

[kygreen229]

bought a auto zone air filter for the se50,,removed the stock air box and put her on richened it a bit to try it and the only thing that happend was it sounded like a chain saw hauling *! so if want to keep this on there i need to rejet it correct? what is stock and what do you think i would need to go up to? or should i loose this air filter all together? thanksl guys

[bradthreee]

Pull your plug and see what its doing:

Ideally you want a cardboard color.

If the plug is coming out light then you will need to upjet.

[Bear45-70]

Go here for enough "reading spark plugs" info to make your head explode, with pictures no less.

http://images.google.com/images?q=readi ... e&resnum=1

[Kenny_McCormic]

You want a co-co brown color, little darker is alright but lighter isn't.

[mr pibbs]

took the liberty. I thought this one was informative.

[kygreen229]

nice thanks for the pics! ya i just wanted to make sure i can watch it and c what happens then upjet if i have to.

[Bear45-70]

Anything past #20 is a no-no with these little air cooled 2 strokes.

[kygreen229]

so i have the air/fuel mixture screw turned out about a full turn...i know stock starting point is a turn and a half..think this is a good starting point or should i turn it out even less? thanks

[Bear45-70]

so i have the air/fuel mixture screw turned out about a full turn...i know stock starting point is a turn and a half..think this is a good starting point or should i turn it out even less? thanks

The only thing the fuel/air mixture screw controls is idle mixture. The chances of hurting the engine at idle are next to none. Just adjust the screw for the highest idle speed. The main jet and only the main jet contols fuel and air mixture at WOT and that's when you melt a piston. You do know how to do a "plug chop" to check the mixture, don't you?

[kygreen229]

a plug chop?? no i just know about looking at the color of the plug and seein if it is lean or rich... so there is a idle screw and then the the mixture screw on the carb right? the mixture screw is only an idle screw mixture as well? whats the point of the idle screw then..im confused

[Bear45-70]

a plug chop?? no i just know about looking at the color of the plug and seein if it is lean or rich... so there is a idle screw and then the the mixture screw on the carb right? the mixture screw is only an idle screw mixture as well? whats the point of the idle screw then..im confused

A plug chop entails running your machine at WOT for at least 2 minutes and then hitting the run/stop switch to stop the engine and coasting to a stop and pulling the plug and looking at the plug to determine your mixture is. Reading a plug any other way tells you nothing important about your engine's fuel and air mixture at speed.

Yes, two idle adjustments, one to adjust the fuel and air mixture for the highest possible rpm. The second screw allows you to adjust the idle speed to the 1800 + or - 100 rpm that is speced in the manual. I have never seen a carburetor without an idle speed adjustment, even if the idle mixture was controlled by a jet (thanks EPA for nothing good) rather than a screw.

[mookie]

2 minutes is a long time at WFO.and if the engine is lean?
about 1.5 minutes in(or less) things get REAL Hot.
tuning big bore kits is serious business

[Bear45-70]

2 minutes is a long time at WFO.and if the engine is lean?
about 1.5 minutes in(or less) things get REAL Hot.
tuning big bore kits is serious business

True, very true, but "good" plug reading take awhile even with a new plug. Back when I drag raced, the plug readings were iffy at best after a quarter mile pass.

[kygreen229]

a plug chop?? no i just know about looking at the color of the plug and seein if it is lean or rich... so there is a idle screw and then the the mixture screw on the carb right? the mixture screw is only an idle screw mixture as well? whats the point of the idle screw then..im confused

A plug chop entails running your machine at WOT for at least 2 minutes and then hitting the run/stop switch to stop the engine and coasting to a stop and pulling the plug and looking at the plug to determine your mixture is. Reading a plug any other way tells you nothing important about your engine's fuel and air mixture at speed.

Yes, two idle adjustments, one to adjust the fuel and air mixture for the highest possible rpm. The second screw allows you to adjust the idle speed to the 1800 + or - 100 rpm that is speced in the manual. I have never seen a carburetor without an idle speed adjustment, even if the idle mixture was controlled by a jet (thanks EPA for nothing good) rather than a screw.

alright cool i will do that for sure! i have nvr heard of that before, crazy. so back to the idle screw and mixture screw the mixture one is lets say your main adjustment when at idle and then the idle screw is for fine tuning the idle..sorry if im driving you crazy im just making sure i fully get it

[Bear45-70]

You set the mixture screw first, to the highest rpm possible. Factory starting place is 1 3/8 to 1 1/2 turns out. I prefer to then turn it a quarter turn richer as it helps off the line acceleration because these carbs have no accelerator pump, but that's just me. Then you adjust the idle speed with the throttle stop screw (1800 + or - 100 rpm)