Fuel level

[GONDARMAH]

Hello to all

I think that float height isn´t the more important for a good running. The more important is the level of fuel into the bowl. With Dell´Orto it is difficult to verify but this could be done installing a Malossi Clear Floatbowl Kit, like this

https://store.bevelheaven.com/carb-fuel ... kit-phf/m/

Of course, it is essential knows the level correct ofthe fuel. Some manufacturers of carbs say the level but Dell´Orto no

somebody knows?
somebody has experimented with this?

Thanks

Gonzalo

[Zanetti]

The float height controls the level of fuel in the bowl and is critical to correct fuelling, to high and the bike will run rich in the mid to high rev range, to low and it will lean out.
The flow of fuel into the bowl is controlled by the needle-valve and it should be selected correctly
"the fuel inlet valve size, stamped on the seat of the needle-valve itself, should always be 30 % greater than the main jet size."
Read through this guide it explains everything pretty well http://www.ducatimeccanica.com/dellorto ... lorto.html

Also the screen on the tank petcock and the mesh filter in the carby inlet banjo should be clean to eliminate any problems with the float/needle-valve and seat
Those clear float bowls were always a bit dodge, have seen them crack through over tightening and discolour over time

[GONDARMAH]

We say the same. Check float hight and check level fluel is the same, but I think that measuring the fuel level is the best way of setting up the float chamber..
Look "Notes On Rebuilding the Amal Mark 1 Concentric Carburetter",

"The correct fuel level for all Mark 1 Concentric carburetters is 0.21” plus or minus 0.040” below the top edge of the float bowl. Thus when the needle valve is being held shut by the tangs of the float, the level of the fuel will be between 0.017” to 0.25” (4.33mm to 6.35mm) from the top of the bowl.

The fuel level can be checked by removing the float chamber and observing fuel running into it. The fuel flow should be sufficient to hold the needle valve open until closed by the action of the float. Insufficient fuel flow will cause the needle valve to seal under it's own weight before the float rises far enough to press the valve shut. The level of the fuel can then be measured down from the top surface of the float chamber.

The fuel level can also be checked by attaching a piece of clear tubing to the bottom of the float chamber. A plastic float chamber drain plug can be modified to mount a suitable spigot, such as an old jet, to attach the tubing. Route the tubing in a vertical position alongside the float chamber. Open the petrol tap and fill the float chamber with fuel. If the fuel level is in the correct range the fuel will rise in the tube to a point between 0.170” and 0.240” below the top edge of the float bowl. Start the engine and ensure the fuel level remains within the correct parameters."

Whith Clear float bowls is possible check fuel level, only for check

[radecal]

Amal Concentrics and Dellortos are two different ball games.
"Insufficient fuel flow will cause the needle valve to seal under it's own weight before the float rises far enough to press the valve shut" doesn't apply to the Dels as the needle valve can only be closed by the float pushing up on it when the chamber is full of fuel to the correct height. No fuel or low fuel in the bowl means the needle is off the seat and fuel flowing in. As the fuel is being drawn out of the carby during engine operation, the level drops and the floats compensate to keep the level in the bowl at the optimum which for our PHM and PHF carbs is between 17.5 and 18.5mm.
So the float height sets the optimum fuel level in the bowl so the statement for the Amal, "The fuel level can be checked by removing the float chamber and observing fuel running into it" won't work! Fuel everywhere!!!
Regards,