[joes] [joes]


Help 81: Amal Mk I Concentric Float Level

Of all the adjustments you can make to your Amal Mk I Concentric, the float level is probably one of the most important adjustments. A lot of people believe the float levels on the Concentric are set at the factory and do not need to be checked. Nothing could be further from the truth.

Although the position of the plastic float is important, what we are really hoping to achieve is a standardized fuel level within all the float bowls on the same bike. The real objective is to achieve the same height on the surface of the liquid fuel in the float bowl, so that the fuel can be the same distance from the throat of the carburetor. Therefore, if you are racing and really want accurate carburetion, then the thing to do is to measure the fuel height and not the float height. The correct fuel height is 0.170 to 0.240 inches below the bowls mating surface.

The method of adjustment is as follows.

1. Determine if the level needs to go up or down. Float level is changed by moving the brass fitting imbeded in the float bowl inlet up or down.

2. Heat the float bowl with mild heat. A hair dryer seems to work better and be much safer than a torch

3. To raise the fluid level, lightly tap the top of the brass float valve seat with a 0.375 inch diameter drift, driving it downward a very small amount

4. To lower the fluid level, lightly tap the bottom of the brass float valve seat with a 0.125 inch diameter drift, driving it upward (up through the fuel inlet) a very small amount

5. Recheck your setting

Remember:

- Each time you change the float bowl, float pin, plastic float, or float valve, the float level must be checked and readjusted if necessary.

- If you disassemble 2 carbs in the same work area, do not intermix the float bowl parts.

-If you are running the bike with the old nylon float needle (white Float needle), get a new "rubber" tipped float needle (metal and black tipped Float needle)


Return to BBC Home Page

Copyright©1997JOES GARAGE No Rights Reserved