Enricher "choke" circuit question....

[gamorg02]

Just a quick question to help me better understand carbs.

When you pull out the 'choke' its not really a choke, it dumps more fuel, so it makes sense it runs better at cold with it on since it needs more fuel to run properly.

However once the bike is warm, if you turn on the 'choke' slowly, the idle speed will slowly raise up to 3-4k rpms. if the butterfly valves aren't changing then wouldn't this mean the carbs are dumping more fuel into the mixture making it go more rich. If this is the case, why does the idle speed keep going up instead of dying?

Or does the slow increase of gas slowly raise the idle speed and allow more air through which pulls the diaphragms out a bit, allowing the idle speed to skyrocket and still keep with a legit a/f mixture ratio?

 

[gamorg02]

just realized no one ever answered this. anyone have any thoughts?

 

[maleko89]

My idle will go up when cold but once warm it wants to stall if choke is applied. When you open the choke it allows fuel from the float bowl to enter a separate circuit in the jet block and exit just below the butterflies. It operates solely on vacuum just like the coasting enrichener circuit. Also, when you open the choke the choke vent on top of each carb is opened.

 

[gamorg02]

mine always has before and after jet kit will go faster and faster if the choke is applied (slowly).

whats the coasting enrichener circuit? and where is the choke vent, does that let more air in?

 

[alorio1]

Can't be related to diaphrams, they are above the butterflies. I have taken my finger, while the engine is running, and pushed open a slide, all it did was pour fuel into the intake and the engine started loading up on that cylinder. I too, am interested in finding the answere to your question.......

Just a quick question to help me better understand carbs.

When you pull out the 'choke' its not really a choke, it dumps more fuel, so it makes sense it runs better at cold with it on since it needs more fuel to run properly.

However once the bike is warm, if you turn on the 'choke' slowly, the idle speed will slowly raise up to 3-4k rpms. if the butterfly valves aren't changing then wouldn't this mean the carbs are dumping more fuel into the mixture making it go more rich. If this is the case, why does the idle speed keep going up instead of dying?

Or does the slow increase of gas slowly raise the idle speed and allow more air through which pulls the diaphragms out a bit, allowing the idle speed to skyrocket and still keep with a legit a/f mixture ratio?

 

[maleko89]

I've never tried that. I turn off the choke after a couple of minutes and after bike will idle smoothly on its own. Choke is needed because fuel "sticks" to cylinder walls due to condensation.

The coasting enricher controls PAJ2. The plunger cuts this jet off when the throttle is closed at high vacuum. It richens the pilot circuit to prevent lean popping.

The choke vent is the small hole on top just above the choke plunger. It's just a vent and allows the choke circuit to move fuel. Otherwise it would be like capping off the float bowl vent. No fuel would move from the float bowl and your bike would stall.

 

[gamorg02]

gotcha. try it next time you ride. another example. if i put my choke on full, started the bike cold and just let it run i would eventually find it warmed up idling at like 4k rpms, as long as it wasn't over 90 degrees out.