40 mpg carb
Joined: Mar 2001
Posts: 31,837
Likes: 3,233
From: https://www2.mazda.com/en/100th/
I'd remove the spring from the diaphragm, so in theory the secondaries should have been opening immediately. I never actually looked, mind you, but doing this did fatten up the midrange nicely.
I did the experimentation with half spring, 2/3rd spring, etc, but I was always happiest with no spring.
I did the experimentation with half spring, 2/3rd spring, etc, but I was always happiest with no spring.
carb whisperer
Joined: Jan 2008
Posts: 1,485
Likes: 4
From: Greenfield, Ohio
Ive been building a custom nikki using some of what I learned from my yaw, and sterling. I kept mine vacuum secondary and I really see no need for a acc. pump mod at all.
I think that was only for mech secondaries that they would "need" a mod there.
I also have tried no spring, 3/4 spring, 1/2 spring, and stock, and I actually prefer stock on my carb. If you mod the nikki for airflow like a Sterling or Yaw, it doesnt seem to like the early opening secondaries you can get away with if its totally stock, and you get a slight surge/bog when they open, regardless of throttle position if running a cut or removed spring.
Of course my airflow mods and stuff are based off of an early "only 410 cfm" or something sterling, so I cant be totally sure.
In terms of mods made to the carb, the only thing I did different than sterling was retain the choke, but I did that my way
I milled the carb airhorn to accept the early larger choke plate, so there could be an airflow increase right there that I cant really gauge since I dont have a flowbench :C
I think that was only for mech secondaries that they would "need" a mod there.
I also have tried no spring, 3/4 spring, 1/2 spring, and stock, and I actually prefer stock on my carb. If you mod the nikki for airflow like a Sterling or Yaw, it doesnt seem to like the early opening secondaries you can get away with if its totally stock, and you get a slight surge/bog when they open, regardless of throttle position if running a cut or removed spring.
Of course my airflow mods and stuff are based off of an early "only 410 cfm" or something sterling, so I cant be totally sure.
In terms of mods made to the carb, the only thing I did different than sterling was retain the choke, but I did that my way
I milled the carb airhorn to accept the early larger choke plate, so there could be an airflow increase right there that I cant really gauge since I dont have a flowbench :C
Joined: Mar 2001
Posts: 31,837
Likes: 3,233
From: https://www2.mazda.com/en/100th/
back in the day when pro7 was hot, people really spent a lot of money/time to figure out what works and what doesn't. often they would start with a NEW engine, like new housings/rotors.
for the carb, the 79-80 air horn LOOKS better, but doesn't flow as much, the 81-85 is better.
the air cleaner they initially swiss cheesed them, but then found that it works better when you have the snorkel to fresh air.
personally i always ditched the choke plate, but kept the fast idle parts
for the carb, the 79-80 air horn LOOKS better, but doesn't flow as much, the 81-85 is better.
the air cleaner they initially swiss cheesed them, but then found that it works better when you have the snorkel to fresh air.
personally i always ditched the choke plate, but kept the fast idle parts
