Installation
1. Place the carby over the studs in the manifold and secure with nuts.2. Slide the OMP linkage arm through the lever and insert a cotter pin to secure it.
3. Connect the OMP lines to the nozzles.
4. Connect and secure the fuel lines, main fuel line to the larger nozzle and return line to the smaller nozzle.
5. Slide the tab on the end of the accelerator cable through the hole in the throttle lever.
6. Secure the accelerator cable by tightening the two nuts onto the bracket.
Tuning
Before starting the engine, turn the ignition on until you see fuel in the float bowls, checking that both sides are roughly in the center like in the picture below. If one or both over-fill with fuel, turn the ignition off immediately - this means the needles are stuck open, which often happens on fresh rebuilds. Hit the carby several times just above the overfilled bowl with something soft edged. This will free up the needles and get them seating properly. The fuel level should then return to the center after the engine runs for a few moments.
The other thing is to prime the accelerator pump (AP). Look down the barrels at the AP nozzles (centre of pic below), and pump the throttle by hand several times until you see a clean shot of fuel coming out both sides. This can be hard to see as its a very thin stream.
When first starting the engine it probably won't idle correctly. To set the idle, turn the bottom (fuel) screw clockwise until the engine hunts (leaning out), then back it off until it runs smooth. Then adjust the top (air) screw until the desired idle speed is reached - turn clockwise to lower RPM, anticlockwise to raise RPM. Then repeat the first step with the fuel screw.
Dyno / AFR tuning
There are peak power gains to be had by dyno tuning the RX-Nikki. I use a generic secondary jetting that will not be perfect for every application. The secondary air jets may need to be changed, as these will control the mixture at peak RPM. Remove the screws and center bolt from the top of the carby, and gently lift off the air horn, being careful not to break the gasket. I have highlighted the secondary air jets below.
The booster venturis may move when you unscrew the air jets. If so they will need to be re-centered. Take note of the number on top of the jet, and then let me know if it's too rich or too lean. I am happy to post off spare jets as long as you can return the unused ones.
