pod filters vs. stock air box

[TopCatGr58]

Hey Rob,

I remember folks doing flow tests with the OEM petcocks and tubes, and the tank flow was rather quick, much quicker, like being able to empty the tank in about 10-15 minutes, can't do that running WOT at 80+MPH for an hour! JAT!
T.C.

[79XS11F]

That's true TC but that's a open line onto the ground (into a fuel can I hope LOL ) with the fuel in the tank crating some pressure in addition to gravity feed. When forcing fuel through the float valve the valve will control the max flow rate that is achievable but to reach that max flow rate some pressure is required and the fuel in the tank and the lines creates that added pressure.
Rob

[Pat Kelly]

My LG is plumbed to where I can run off of either one or both petcocks. When running on one petcock I have no loss of power due to not enough fuel flow. It runs just fine at WOT or cruising in the upper RPM range for XStended periods on one petcock (1/4" fuel line).
The LG has the 1196 big-bore kit and K&N filter in stock airbox.

[fredintoon]

My calculator went missing

but by mental arithmetic and rounding off the numbers (3 is easy to do, Pi is not ) ; the maximum fuel flow through the carbs has to be whatever amount can get through the four main jets. Say the hole through the main jet is 1mm diameter then the area of 4 of them = ~3 sq.mm. Fuel flows towards the carbs down a 3/16" (~5mm) diameter hose which has an area of ~15 sq.mm.
Thus the fuel delivery available to the carbs down one fuel hose would appear to be ~5 times the maximum demand.

[John]

The numbers have spoken

Thank you for doing the math Fred.

I ran mine on just one petcock for many years. I did have both petcocks plumbed in, and I could choose either petcock to use, that way I didn't have trapped, unaccessable fuel in the tank. When my low fuel light came on, I would just open the second petcock and all the fuel was available.

[79XS11F]

The jetting does indeed control how much fuel the engine will receive. There's no doubt about that. However if that was the only contributing factor there would be no reason to worry about how much fuel is in the bowl and the fuel level in the bowls would have no impact on how the engine runs. We know this is not true and fuel level in the bowl is a very important part of the whole setup. It only stands to reason that how much fuel is available to refill the bowls would therefore also be an important part of the set up. If it wasn't then all bikes regardless of engine size and carb set up would likely come with fuel lines of the same 3/8 inch size or whatever was the most compact. If fuel delivery to the bowls was not an issue then it would make no difference if the lines, petcock screens etc were not working properly and we also know this is not the case. We know that our engines will not run properly if 4/5 of the fuel flow is missing.
Rob