Hey all, I'm looking to do a mild street port on the outer irons of my spare 12a, and I'm trying to get more info on what I'd need to do to modify the secondary circuits in my Nikki to match that.
I've been trying to do research on it but all of the old posts on a similar subject just end up saying to send it to Yaw or Sterling. Am I correct in assuming that neither of those are an option anymore? If so that's an option I will explore, but if not I'm willing to try modifying my spare carb to accommodate.

What would need to be done? New jets? New Air bleeds? I'm not an expert at carb modification but I understand the basic principles and am willing to learn more. Help me gods of Nikki!

 

You can read my post linked in my sig and I also highly encourage you to search for all of Jeff20B posts here on nikkis and carbs. We now know a lot more and better things than Sterling or Yaw even dreamed of thanks to Jeff mostly.

 

A stock Nikki with some upped main fuel jets will work on a mild street port decently well, although you're not getting much more power that way. Getting more power NA requires removing restrictions. For our Nikki's this means trimming boosters, removing the choke, hogging the venturis, less intrusive throttle plate screws, etc.

I would also consider porting all the irons the same. With the Nikki manifold the ports are connected, so some airflow is going to all of them at the same time. Also you won't have an issue with overlap if it's a mild port, such as "74 spec". I pass smog easily with my medium-mild ported 12A (slightly beyond 74 spec).

A lot of the extra power from the Nikki comes on the primary side (talking venturis here). Most people who mod Nikki's do the primaries, not as many mess with the secondaries.

I've got a thread on the subject as well, although it's a bit of a mess. I never intended for it to be a "how-to", it's more of my progress/assistance log. Regardless, it's got some good and rather up to date Nikki modding info if you spend the time to pick through it. Once I finally wrap up my Nikki (really all that's left is a little more idle circuit tuning and some AP changes) I'll post a condensed version with what all I learned.

Best of luck! The Rotary Gods will be pleased to see another Nikki build.

 

Modding the exhaust system is the most important thing you have to do.