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If you are not running "optimal" on the A/F ratio....then is it better to run slightly rich or lean? What happens if you do tend to run too rich or too lean? What is better for our engines and which is worse?
 

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I am far from an expert but if there has to be a choice for a period of time to run lean or rich, I would choose rich. Running lean can give you more power but to lean will blow your engine. Running too rich can also hurt your motor.

Think of it when you are mixing gas for your weed wacker. It is always safe to add a little more oil than not enough to the mixture. Just running a little lean or a little rich will not hurt anything for a while. If you run to rich for a period of time it will make your bike run like crap and fool your plugs.

If you look at your plugs and they are white you are running a lean cond. If they are caked in black you are running a rich cond. I believe a nioce golden brown is what the plugs should look like.

If you are not running "optimal" on the A/F ratio....then is it better to run slightly rich or lean? What happens if you do tend to run too rich or too lean? What is better for our engines and which is worse?
 

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Rich. Lean can drive up combustion temps causing all kinds of nasty things to happen. Rich mixtures kill power a bit and waste fuel ( the extra fuel actually acts to remove heat from the combustion process causing the power loss.
Ed
 

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I am far from an expert but if there has to be a choice for a period of time to run lean or rich, I would choose rich. Running lean can give you more power but to lean will blow your engine. Running too rich can also hurt your motor.

Think of it when you are mixing gas for your weed wacker. It is always safe to add a little more oil than not enough to the mixture. Just running a little lean or a little rich will not hurt anything for a while. If you run to rich for a period of time it will make your bike run like crap and fool your plugs.

If you look at your plugs and they are white you are running a lean cond. If they are caked in black you are running a rich cond. I believe a nioce golden brown is what the plugs should look like.
Hello i just want to ask something regarding my carburetor. I tune my mixture screw in maximum tight because when i looses half of it my engine feels like choking. I tight it in maximum setting s because thats the compatible fuel and air mixture that my engine will run smooth but the problem is my sparkplug turns into black color. So thats the indication that i run rich.
i hope can help me. Thankyou.
 

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Hello i just want to ask something regarding my carburetor. I tune my mixture screw in maximum tight because when i looses half of it my engine feels like choking. I tight it in maximum setting s because thats the compatible fuel and air mixture that my engine will run smooth but the problem is my sparkplug turns into black color. So thats the indication that i run rich.
i hope can help me. Thankyou.
Optimum afr depends where in the rpm it is needed or it can be custom taylored to a task or blend of fuel as Ethanol blends need a hair richer . For example, I run 14.55 ish at idle, 14.62 cruise and at higher kpa load and higher rpms it transitions richer to the max richness of 12.5 at wfo. So many base cals come with a cookie cutter afr settings. I can't tolerate that. LOL Most too rich at ilde an cruise for smooth running an good fuel economy. Even at my above afrs, my plugs are ever so slightly showing toward the richer side but plug reading really can't be trusted with today's fuels. Not like the old leaded days. A safe lean is 14.7 and the stock v rod cals even exceed that in areas to pass EPA but it does generate a lot of heat. Constant fan cycles etc as a result.
Ron
 

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Optimum afr depends where in the rpm it is needed or it can be custom taylored to a task or blend of fuel as Ethanol blends need a hair richer . For example, I run 14.55 ish at idle, 14.62 cruise and at higher kpa load and higher rpms it transitions richer to the max richness of 12.5 at wfo. So many base cals come with a cookie cutter afr settings. I can't tolerate that. LOL Most too rich at ilde an cruise for smooth running an good fuel economy. Even at my above afrs, my plugs are ever so slightly showing toward the richer side but plug reading really can't be trusted with today's fuels. Not like the old leaded days. A safe lean is 14.7 and the stock v rod cals even exceed that in areas to pass EPA but it does generate a lot of heat. Constant fan cycles etc as a result.
Ron
But i think my carb is not normal because i set the fuel and air mixture in maximum tightness settings. So the settimgs is all has no aircing but the rpm of my scooter
Is not cutting It goes very well.
 

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But i think my carb is not normal because i set the fuel and air mixture in maximum tightness settings. So the settimgs is all has no aircing but the rpm of my scooter
Is not cutting It goes very well.
Not sure why we are talking carbs here but what the hell?. That's a different ball game. If you need the screw(s) in that far, there are a few possible reasons. Jet too large, float bowl level too high if it's the high speed circuit. For the low end same thing as in jet too large or possibly enricher not closing off if the carb is so equipped. Mind you, the carb needs to be matched to the engine as well. I don't know if your's is stock or one that's too large for the engine and trying to make it work.
Ron
 

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Not sure why we are talking carbs here but what the hell?. That's a different ball game. If you need the screw(s) in that far, there are a few possible reasons. Jet too large, float bowl level too high if it's the high speed circuit. For the low end same thing as in jet too large or possibly enricher not closing off if the carb is so equipped. Mind you, the carb needs to be matched to the engine as well. I don't know if your's is stock or one that's too large for the engine and trying to make it work.
Ron
Thankyou sir for your reply. It helps a lot btw im using stock carb only ang my scooter is only yamaha jog 50. You’re talking about fuel jet right not the fuel needle. Thanks sir
 

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Thankyou sir for your reply. It helps a lot btw im using stock carb only ang my scooter is only yamaha jog 50. You’re talking about fuel jet right not the fuel needle. Thanks sir
Yes, in that case jet and needle for high speed circuit. Idle will be an air screw , based on what I dug up on it. I'm not familiar with it otherwise but here is a link that explains some of it. Since we are now talking 2 stroke I prefer to error slightly rich at top end. Low end, best smooth running. The correct needle position and jet should give you the top end for fuel.
Ron
 
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