Bingo! You need to rejet. If you need help, just tell us and we'll get you through it.TimberPig said:Your math is off, it's actually 20% not 25%, but it matters little anyhow, as the change in the air/fuel mixture received by the engine is only about 1%. This is because the engine can only draw a fixed volume of fuel through the carb jets. Also by going to 40:1 from 32:1, you are actually increasing the fuel in the air/fuel mixture and thus making the air/fuel richer, which will equal more spooge not less. If you really feel the need for a premix ratio change, go ahead, either 32:1 or 40:1 is fine, but to stop your spooging problem, you need to rejet, not mess with the mix ratios. Pick a mix ratio, and then start setting up the jetting with it.
crazyrydermx said:Bingo! You need to rejet. If you need help, just tell us and we'll get you through it.
motometal said:this is not something that can be easily calculated with math, guys...you would have to account for the viscosity of the fuel and oil, the differential between the two, etc
although ratio does affect jetting, I would doubt that it would affect it more than one jet size on the main or one clip position on the needle, going from say 32:1 to 50:1.
TimberPig said:Maybe you should read this
Carb Tuning
as it sounds like you don't really know how to correctly approach jetting a bike.
TimberPig said:A partially fouled plug could reduce the strength of the spark enough to make it bog as if it was lean. Sounds alone isn't a reliable tuning indicator. You need to combine sound, feel, throttle response and plug burns to get a good idea of how the engine is responding and whether the jetting is correct.
TimberPig said:Actually it could be calculated very easily with math, using fluid mechanics, but all he was basing it on is a simple reduction/increase in the amount of oil in the mix, which is not the amount by which the air/fuel ratio changes.
motometal said:it depends what you call "easily", first you would have to know the viscosity of both fluids, which I don't believe we do. Or, given the viscosities, we would have to combine this calculation with the calculation above relating the differential in actual gasoline, which isn't actually accurate anyway because a certain fraction of the oil burns, which can vary according to combustion chamber temperature. The other assumption made here is that there won't be any type of chemical reaction between the oil and gasoline, altering the net viscosity of the mixture.
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