Well, that black wire with the white stripe and the lime green connector has to be hooked up to an ignition-switched 12V+ source. That is the float bowl vent solenoid. It's confusing if you don't know what's inside.

The FBS consists of an electromagnetic camber with a metal piston that fits inside. The piston is spring loaded, and at the other end of the piston is a shaft and a plastic plunger. There is a vent hole that allows the float bowls, which both share the same ventilation that wraps around under the air horn, to "breathe" as fuel enters and leaves. If the hole wasn't there; -if the bowls were not vented, then the fuel would do all sorts of crazy things while it tried to flowinto the main circuit. It's a bit like taking a soda bottle filled with water and turning it upside down. It "glugs". Cut a vent in the top (the bottom of the bottle), and the fluid pours out uninhibited.

Well this vent hole needs to be plugged to prevent fuel vapors from escaping into the atmosphere in order to comply with emissions standards. So when the power to the solenoid is cut, the spring loaded plunger caps off that vent.

The hose nipple on the side will in fact act as a vent when it is uncapped.
So if you didn't have your FBS hooked up, and you then yanked the hose, then "Yes", you would see a difference.

 

i dont know much about jetting but i know you have to increase airflow. for example, putting in thinner butterflys, shaving the butterfly pivots, shaving the chambers ect...just by doing that you can almost increase the airflow by like 100 cfm. Thats what i was told anyways.

 

It's gotta be done right, though.

 

true that, listen to sterling, hes done enough of this **** to know what hes talking about, he will actually literally talk the pants off anyone on this forum about nikki carbs. Hes the man behind the best carb for a rx7. Isnt that right sterling?

 

You lookin' for a discount or sumpin'?

 

haha sure if you wanna build me a carb for my 327 rx7. My other rx7 is going to be a mint stocker.

 

i love the nikki, but when i look for fine tunability and great performance i modify holley's to work (not hard to do).

sterling is right tho about my float/ fuel pressure setup. you do have to tune it as for the best compromise for all gears but i mainly look for best performance out of 3rd and 4th gears. 1st and 2nd will be slightly richer but with MSD firing the **** out of the spark plugs i don't have any problems cuttin the fuel up oh and damn good compression is needed as to pull high hg under idle and cruise. if you have a port job then this doesn't work so well hahahaha, but then i use a different carb setup entirely.

but as i did say, it's not for the weak. if you don't know these carbs well then don't even attempt it. lol