Installation of HIF-6 or HIF-44 Carburetors

General Guidelines for Installation of HIF-6 or HIF-44 Carburetors

These guidelines make several assumptions, among which are:

1)You own a workshop manual covering the SU HIF-series carburetors. A number of good-quality manuals dedicated to the SU are available and are highly recommended. It is strongly recommended that you understand the theory of operation and the mechanical layout of the carburetor before you start.
2)You have installed the intake manifold and carburetor with all correct gaskets and fittings and have obtained throttle and choke cable of sufficient length to correctly operate the carburetor.
3)You have installed at least two throttle-return springs.

General

The HIF-series carburetor differs from the HF-series primarily in:
    1) The design and location of the float chamber, which has been incorporated in the body of the carburetor, and
    2) The introduction of temperature-sensitive mixture control (a bi-metallic strip fitted to the jet adjusting screw mechanism) to compensate for varying fuel densities resulting from changes in fuel temperature.

These procedures cover very generally the connection of both the throttle and choke linkages and provide a key to correctly dealing with the various tubes and ports of the carb.

Choke and Throttle Cable Setup

Route the cables as required for your particular installation and connect them to the linkage attachment points. Adjust both cables to give full range of motion without binding. The gas pedal should open the throttle fully at the same time it hits the floor. If the pedal travel is stopped by the throttle reaching the full open position, the result will be stretched and/or broken cables, bent linkage parts and increases the possibility of a jammed or sticking throttle.
Make sure that the linkage is free of any bind or interference and that it the return springs close it completely when released.
The choke cable requires the same care. Adjust the cable such that it gives the full range of motion with no binding, taking particular care to see that it completely disengages when the choke cable is pushed to the fully off position.

Needle sizes generaly used in 1 3/4" SU's for 1300 based engines.

When choosing a different needle, select one with the same idle figures if not possible then Remember:

* If new needle has a leaner idle figure, the reat of the needle will give a slightly richer mixture than the profile suggests.

* If new needle has a richer idle figure, the rest of the needle will give a slightly leaner mixture than the profile suggests.

This is all caused by repositioning of the jet to get correct idle.   This is a rough guide only!