Correct size needle valves

[Tobyjugs]

Hi chaps, does anyone know the correct size needle valves?
The reason i am asking is because when i go onto reserve, i have to wait a while before the carbs are filled enough to work again
Today was real bad because was driving between all the slow moving traffic when i hit reserve, i reacted fairly quickly but it must have taken at least 400 meters before i was running on two cylinders properly.

[fatfastroger]

It might be you have a blocked filter in the tank ?
Think there is only one size float valve too

[Tobyjugs]

The fuel system is very clean. I can rev the nuts off it and it's ok. Just seems to take a while before i can use it after i go on reserve.

[4l04ever]

The actual feed to the float valve is very small on standard LC carbs. Also, the fuels pressure would be lower when there is less fuel in the tank, so the two things together could make the float bowl take a few seconds to fill back up. The small cross drilling is the main restriction. It could be partly blocked. I have also seen sh1t under the valve seat. Take the seat out and blow through the fuel inlet pipe to make sure the pipe is clear.

[muttsnuts]

could be the reserve filter on the tap, the guaze filter that fits onto the fuel tap that goes inside the tank has a tall one and a short one (internally), if the filter is blocked lower dwn then fuel will struggle to get out of the tank through the partially blocked filter.

Quickest way to test it is to get a measuring jug/container, time how long it takes to fill it to a given point when the fuel tap is set to the on the position, then drain the tank until it goes onto reserve, then repeat the test with the tap set to the reserve position, if there is a difference then that's your problem

HTH

[Tobyjugs]

Thanks for the suggestions everyone when i get some time i will let you know how i get on.