Main Air jet removal

[motoman]

You are correct that with increased airflow and no back pressure the carbs should be running lean not rich, which is what has been throwing me off (by the way the plugs are black and covered with carbon). These engines do not like backpressure, the carbs are designed for a specific air flow rate. Every engine will be more efficient and more powerful with less pressure drop on the intake and exhaust. The reason that no one is able to run these bikes without backpressure is the air eductors on the carbs. A typical carburetor uses vacuum in the main air passage to suck fuel into the engine. These carburetors use the above but also use an eductor powered by the inertia in the velocity stacks to pull additional fuel into the engine. What this means is if you significantly reduce backpressure and increase airflow (which I have done) these carbs will run richer due to the increase in fuel flow from the eductors which is counterintuitive for carb tuning. I have also removed the original octopus fuel system and replaced it with a much simpler gravity feed system with a fuel filter. I have the newer model carbs with the plastic floats. What are the vent hoses you are referring to?

educators???? Understand your theory behind what you stated, but actually is just the opposite. The vacuum diaphrams that control the slides/metering rods in these carbs are dependant on a CONTROLLED vacuum gotten from the stock airbox intake. When jetted properly, this allows CORRECT positioning of the vacuum slides depending on vacuum in a particular rpm range and allows a realatively correct fuel/air mixture through-out ALL rpm ranges. THIS is the reason, other than WOT that performance suffers on one end of the rpm range or the other when using open pod intakes or non restrictive exhaust. Pods were designed for WOT running at the strip, not the street with variable rpm ranges. Same goes for non-restricted exhaust, tuning motor for WOT.