Thinking of re-routing the fuel lines...

[Lucien Harpress]

I'm going to have the take the carbs off my bike (again) here pretty soon, and I got to thinking this would be a good time to change the setup of my fuel lines. Right now I've got the two-line setup (right petcock goes to left two carbs, left petcock goes to the right two carbs, with fuel filters in each), but I'm tired of having only two cylinders fire up because the bike has been sitting on its sidestand for so long.

Here's my idea. Take the two petcocks and connect them, straight across under the tank, with a T fitting so they both funnel to one line. In this line put a fuel filter, then ANOTHER T fitting to split the line back into two. These two then go to the carbs. This way, even if I only have one petcock working at a time all four carbs will be getting filtered fuel. It might fit a bit better, too- as it is there's a bunch of places for air bubbles to get stuck. Is this a good idea, you think? Or am I barking up the wrong tree?

[Cobia]

You may want to use a larger filter than those usually fitted for the individual lines. You do not want to starve it for fuel. Unless you're running very low on gas where one side of the tank is dry, the bike shouldn't starve for fuel while on the sidestand.

[DGXSER]

There are several folks who run the set up you describe. I think BikerPhil may have one of his set up like that.

I feed mine from the same side petcock. Being a special, the vacuum valve used to live elswhere. I run from the ON outlet straight down between the #1 and #2 intake boots, put one of those clear triangular fuel filters in the line, then run straight to the carb T. Fuel filter will fit between the intake boots. Same thing on the opposite side. I do have to pull the line down to ensure no kinks after raising the tank up. Otherwise, no problems at all.

[bikerphil]

Right now I've got the two-line setup (right petcock goes to left two carbs, left petcock goes to the right two carbs, with fuel filters in each), but I'm tired of having only two cylinders fire up because the bike has been sitting on its sidestand for so long.
Or am I barking up the wrong tree?

The setup you have should work fine. There might be another problem such as a plugged up petcock, a pinched line, vacuum leak or low fuel level. Try running the offending petcock on prime, see if it improves.

Don, the setup I'm running is single petcock to a filter, then into a T, then down to the carb inlets. With automotive fuel line, of course.

[oldyam80sg]

I have Pingle petcocks on mine and the biggest pain -trying to get fuel line to fit over the outlets as they are bigger than the stock petcock and they point downward.Usually have to really press them on.I also run 2 individual fuel filters to keep everything clean and am always looking at a simpler setup-also running the octy but also don't have any starvation issues so i might just leave it.

[Lucien Harpress]

Yeah, the two line setup SHOULD work fine for me, and a lot of times it does. But there are times, especially when I'm low on fuel, where for whatever reason, the fuel on one side or the other doesn't feel like flowing. It's like there's not enough pressure on top to force the gas through the lines. I'm just trying to eliminate a bit of the hit-and-miss from the fuel system.

[yamahansolo]

I am using 2 t's. 2 fuel lines go into a t then into the fat auto fuel filter. 3 bucks for the filters at wally world. Then into another t and into both carbs. I have used it for over a year with no problems

[bikerphil]

Don't forget to check the vent in the fuel tank cap, making sure it's clear.

[TADracer]

Lucien, to end what you are experiencing you need to have a crossover which is preferably below the percocks.. I am not sure what happens on a standard but on a special the crossover occurs in the octy.

Since I have long ago exited my air box, the picture shows how I am set up. Notice the crossover pipe between the fuel feed lines. Works like a charm and one petcock will flow more than all carbs can consume at WOT.

BTW, I made my fuel feed setup with some 1/4" steel fuel line and a few brass fittings and it is all brazed together.

[natemoen]

Nice setup Mike!

[g15usmc]

Lucien, to end what you are experiencing you need to have a crossover which is preferably below the percocks.. I am not sure what happens on a standard but on a special the crossover occurs in the octy.

Since I have long ago exited my air box, the picture shows how I am set up. Notice the crossover pipe between the fuel feed lines. Works like a charm and one petcock will flow more than all carbs can consume at WOT.

BTW, I made my fuel feed setup with some 1/4" steel fuel line and a few brass fittings and it is all brazed together.

what is that little filter for?

[DGXSER]

Those are in line fuel filters. The gas tank petcocks have built in filters, but, it is not unheard of that those could fall off in the tank. Only way you know besides pulling the petcocks out, is when you have no reserve when you need it.

Even with those, smaller stuff can and does make it past those in tank filters that an in line filter like those will catch, before it plugs your float valve open and you get gas running on your garage floor, or worse on your hot engine causing a fire.

So many members, in fact most, use an inline fuel filter something like those. This is the first I've ever seen of the steel fuel manifold like that.

[CatatonicBug]

what is that little filter for?

That is the vent line on the older model carbs. That line (and the one between carbs 3&4) would usually be connected to the little nipples on the front of the airbox. The newer model carbs don't have that line, as they vent directly to the airbox.

[natemoen]

what is that little filter for?

I am guessing he is talking about the float bowl breather filters on the top in the back Don.

The little paper filter you see in the background is for the carb bowl breathers. On the early model carbs the carb float bowls had a vent hole that was connected to the airbox. So when people switch to pod filters they still have the float bowl vent line that is then open to the air. Some people put a little filter on it like that so that dirt doesn't get in the float bowls and some people just leave it open to the air.

[DGXSER]

Yep, it does seem like that was the question, my early mornin' eyes did not even see that back there.