To make tuning those oval bore Fakuni's easier you could temporarily fit a 360 degree carb spacer between the manifold and the head ... A cheaper idea would be to buy another manifold , cut right thru it on the straight part near the carb mount flange , clean the edges up with a file , then fit a piece of rubber radiator hose and 2 hose clamps so that you can turn the carb to the side ...
Some carb tuning info ...
1) Float Height :
The float height controls the fuel level in the float bowl , which can also effect carburetor performance . Set float height according to specification before any other tuning . The float height may need to be adjusted for best performance on different track types .
2) Idle / low speed :
Tuning of the engine at idle and low speeds is accomplished by adjusting the Idle Mixture Screw or changing the size of the Pilot Jet (also called Slow Jet) . The Idle Mixture Screw is a fuel adjustment when it's on the intake manifold side of the slide , so closing the screw or turning it clockwise will lean the fuel mixture , and opening the screw or turning it counter clockwise will richen the fuel mixture .
If the Mixture screw is on the air filter side of the slide it's an air screw , turning it in reduces the amount of air and richens the mixture and turning it out leans the mixture out .
To adjust the Idle Mixture Screw proceed as follows . Turn the Idle Mixture screw in until it lightly seats or stops . Back the screw out the specified number of turns . Warm the engine and set the Idle Speed screw slightly higher than the desired idle rpm . Turn the Idle Mixture screw in or out to obtain the highest rpm . Turn the Idle Speed screw to the desired idle rpm . A slightly rich idle mixture is usually better for acceleration .
If a smooth idle cannot be obtained with the Idle Mixture screw between 1/4 - 2 turns out from closed , a different size Pilot Jet may be needed . The proper size Pilot Jet will allow for smooth acceleration from an idle and steady engine speed up to 1/4 throttle opening .
3) Midrange / Part Throttle :
The Jet Needle primarily controls fuel flow between 1/4 and 3/4 throttle opening . The Jet Needle has five notches and a C-clip on the top of it . To richen the part throttle operation , move the clip to the next lower notch . This will hold the needle farther out of the nozzle . To lean the part throttle operation , move the clip to the next higher position . The highest notch (farthest from the narrow tip) is considered to be the 1st position.
4) High speed / full Throttle :
The Main Jet controls the fuel flow at throttle positions of 1/2 to full throttle . The jet size or diameter in millimeters is stamped on the jet . Altitude and weather conditions can effect the engine operation enough to require changing the size of the Main Jet . High air temperature , humidity , or altitude could require a smaller Main Jet . Low temperature , humidity , or altitude would require a larger diameter Main Jet . Running the engine with an improper Main Jet could result in a loss of power , high engine temperatures , or engine damage.
