Hi 2CV,I did your option 1. I'll upload a photo when I get the chance. Also used a fuel filter with a 90 degree turn on it.~Dan
IMO, it would be almost impossible for the engine to use more fuel than a 3/16" (4.75mm) fitting would allow to flow thru it.These fittings have a hole thru them that's about 3/32" (2.4mm) in diameter or larger.Just imagine a 1 gallon (3.4 ltr) bucket of gasoline with a 3/32" (2.4mm) hole in the bottom. (That's just a bit smaller than 1/8 of an inch (3.17mm) for those of you who don't work with 32th's.)The amount of fuel pouring out of that hole is about the same amount that will flow thru a 3/16 inch fitting and there is just no way a 500cc engine can burn that much fuel.
Understood and agreed...no way can the fuel burn be beyond what a gravity feed stock petcock could deliver. But, why the airlock? Albeit, not a true airlock, as fuel seems to pass at a sufficient rate, this is still an area of constant concern for me. I find myself looking at the fuel line at every traffic light...and continuing to see AIR at the hump.Would a 1/4" petcock keep the fuel line "full"? Does this airlock not concern others, as it concerns me?OR, perhaps I should simply go back to solid color fuel line.
If the hose from the fuel cock first goes down and then has to go upward over something like the head steady and then down to the carb, any air bubble in the high area of the line will continue to rest at the high point of the tube.The only thing that could move it downward would be a massive flow of fuel with enough velocity to force the air downward and out of the line. Of course the small amount of fuel that is actually flowing thru the line isn't enough to do this.I'm sure the fuel level on the fuel cock side of the "hump" in the line where the line goes up over the head steady is at the same level as the lowest height of the inside of the tube where it just starts to go back downhill towards the carb.There is probably another area just below the fuel cock that looks like it has air in it with the top of the fuel appearing at the same level.The reason the carb is getting fuel in spite of these air bubbles is because the small amount of fuel being consumed is trickling down from the fuel cock to the first low area in the tube.It then flows thru to the low level of the tube at the high point and then trickles down to the carb where it flows thru the float chamber valve into the carb.Confusing, but that's the best explanation I can give.If some of the transparent tubing is available use it to make a downward loop which climbs up to a upward loop which again turns downward.Pour some water into the tube and notice how the low area fills with water but the high area of the tube and the exit seem to be empty.Pour some more water into the tube and notice that although the water does flow thru the tube, the air "bubble" at the top of the loop remains "empty".