Ok in the schematic here is says to drill the axial jet to 5/64 but that seems really huge compared to the holes that are stock. And I know people drill out some stok jets. Can anyone tell me what jets (by number on schematic) and what size to drill?
Here's the set up I'm working with
Stock port 12a
Nikki stripped with mechanical secondaries
Cat deletes
No rats nest
Msd direct fire ignition
All emissions and and coasting valve removed.
Stock exhaust manifold for now.

 

**disclaimer: I wouldn't even fool with this until you have a wideband 02 setup installed to monitor AFR's.**

Who wrote the instructions? I'm not sure what the stock jet size is. When I did mine, I used a set of numbered micro drill bits from a hobby store. I found one that fit the stock jet size and then drilled it with the next two largest bits. I did the same with the nozzles. You don't want a huge change or you'll cause a hiccup from it dumping too much fuel. You can always go back and drill more, but you can't undrill it.

The axial jet is the one that controls flow from the accelerator pump. So drilling that out will only effect the amount of fuel you get when you first get on the throttle. It's a mod that's meant to get rid of that lean spike that can cause a hesitation when you first step on the gas. In order to benefit from enlarging the jet, you need to increase the capacity of the pump itself.

Leave the other jets alone until you've at least got headers, a ported intake manifold, and most importantly a wideband. It takes a bit of modification before there's any benefit to be had from rejetting.

 

Working on getting a header. I have no idea who wrote theses instructions? Thanks for the info. That's why I didn't screw with it until I knew for sure.

 

I wrote them, and made the Nikki stripping guide you are using. I have used these sizes on multiple cars and carbs and they will work well on your Nikki. However, keep in mind when you start changing around accelerator pump stuff that your fuel mileage is going to be horrible. I was probably getting 12-15 mpg in my FB, although I desperately needed to do some tuning. So I think there is LOTS of room for improvement in my number without sacrificing any power.

Anyway, you are only drilling the banjo bolt that goes in the top of the accelerator pump casting (#68). I want to be clear that you are not drilling the jets in the fuel bowls. The accelerator pump components that you are working on serve a much different purpose than your fuel jets do. If you don't understand the difference between the two then I would recommend doing some reading/research before you plan to start changing/modifying your carburetor. There are two holes in the banjo bolt. One runs axially through the length of the bolt, and the other shows itself near the head of the bolt as two small holes. These holes do not do any actually measuring or metering of the fuel. They are simply a passageway. By drilling them out to 5/64" you are eliminating the chance of restriction or starvation. Yes, you are correct that 5/64" is WAY WAY bigger than their original size. But you don't really care. Just open them up for more flow.

Now, the actual metering of the fuel takes place in the cast accelerator pump block (#69) that is underneath the banjo bolt. If you look at it carefully you will see two pin sized holes in each of the squirter arms. They shoot down into the barrels of the carb when you pump the pedal. THESE HOLES will actually help meter the volume of the fuel shot from the accel pump somewhat. So you want to carefully drill these two holes to 0.050" with a set of micro drill bits. Drill them by hand. The material is VERY soft. You don't need a drill or a drill press. It will just over-enlarge the holes. Remember these holes are almost the size of a needle. Drill them by hand, take your time.

Hope this helps.
Jamie

 

Yeah that helps a lot! Thanks man.