85 Carb Rebuild
 

I am going to be rebuilding my nikki soon, it's first rebuild. I have no problem rebuilding it, but wanted to ask a couple questions. I know Sterling has several write ups regarding modifications/upgrades for the nikki. My goal is to make the carb a little better than it was originally.

My questions are:

What can I do without modifying too much to help my carb/car out while rebuilding (other than the obvious cleaning and doing the rebuild right)? I've heard of changing the jets and increasing the stroke on the accelerator pump to prevent high rpm power loss.

As far as jets go, should I keep them stock? Or is there a decent benefit without going down to 10 mpg in changing their size?

What should I eliminate? I want to know about the vacuum setup and how the solenoids work. I just recently re did all of the hose routing and cleaned up the solenoids. I wanted to know if there's a way to upgrade them at all (2nd gen? or just mods)

Thanks guys

Getting ready to do this myself. Subscribed for informative posts.

https://www.rx7club.com/showthread.p...threadid=62678

very helpful thread by sterling. I will definitely be using this, as well as any other info found in this thread. good luck to you chev

Thank you! Good luck to you too!

no need to change jets. just get a couple cans of carb cleaner and give it a good cleaning. make sure to keep up with all the check balls and such that tend to roll away when ur not looking. a good idea is doing the disassembly over a rag or towel to catch things that fall out. that acc pump thing is for converting to manual secondaries. which personally i've never had to do when doing this mod. but it's supposed to give an extra amount of fuel shot as the secondaries open at low load.

jets/A.P.
 

So you think I should keep the carburetor itself stock? In other words, no advantage to changing jet size or accelerator pump stroke length?

Just changing the jets in the carb won't do anything if you don;t need the extra fuel. An increase in airflow requires an increase in fueling... if you have modifications (exhaust, header,porting) then you will see benefits from going up a jet or 2 on the secondaries, if you're stock then leave it as is.

Jets
 

If i got the racing beat headers for example would it benefit me to do like u say and up the jet size one or two? Or just a higher flow exhaust, but either way, would it do me any good?

Jets operate proportionate to pressure differential, which is driven by airflow. If you increase airflow you will get an increase in fuel flow from the same jets; whether or not that increase will be enough depends on the flow increase, which is tough to determine without experimenting.

Basically, changing the jets larger both lifts and changes the mix curve. It's not linear.

Back when I had the full RB exhaust on my car, it ran just fine with stock jetting.

I myself would recommend making the exhaust change first, and THEN seeing if your result requires bigger jets, based on whether or not it seems to run lean.

+1

I would leave the jets stock. They're too rich from factory as it is, why go fatter.

Exhaust does change jetting. +1.

leave the jetting alone. i can almost guarantee you're not going to need to change them without first doing something really drastic to your engine.

this subject has been covered a bunch of times. :icon_no2: The search button is your friend and www.sterlingmetalworks.com