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Petrol in Air Filter
whitestu - 1/8/08 at 03:07 PM

With my bike carb set up [ZX6R carbs, pipercross sausage filter on 1.8 Zetec] I find that the bottom of the filter is soaked in petrol after a run.

The carbs aren't installed at an angle like on the bikle - they are mounted horizontally.

What I want to know is whether this is happening because of how the carbs are mounted [I suspect it is].


If it is then I guess I need a proper manifold rather than my current set up using the bike rubbers mounted to an ali plate.

Otherwise the carbs work perfectly andI've never seen fuel actually dripping out with the filter off.


Thanks

Stu


britishtrident - 1/8/08 at 03:24 PM

If not flooding it could be stand off --- the airflow through the carbs on a one venturi per cylinder setup is pulsing and not all of it is going into the cylinder at one point in the cycle ia pressure pulse reflects back from the valves towardsthe carb. The causes a cloud of fuel vapour and dropplets ("stand off" in the vicinity of the carb mouth.

If the volume of the air filter is small this can cause the filter elrement to get soaked in fuel

[Edited on 1/8/08 by britishtrident]


Mr Whippy - 1/8/08 at 03:27 PM

as above, I have felt my hand get damp when held over carbs before, some times you actually see them spitting fuel. Just don't light a match.


mr henderson - 1/8/08 at 04:25 PM

One of the reasons why trumpets are fitted to this type of set up is to contain standoff.