Modest beginnings of my M750 project

[MendoDave]

Check the float bowls, sounds like they might be stuck in the down position.

[memper]

Thats what I was thinking.

What tells the pump to stop pumping? Does it get a sense when the float chambers are full and stops pumping? I ask because I turned the key and let it sit that way for 30 seconds and the pump never shut off. I thought pumps ran for a sec when the ignition was turned on but then it stops. And only come on when necessary. Do I have the wrong understanding? (Highly likely)

[ducpainter]

The terminals have them as well as the hole thingy. Anyways I figured the return pipe connects to the vent hole on the gas cap.
New issue: turned on the ignition, pump started whirring, I open the manual fuel tap and gas just started gushing out of the carb overflow lines. Any idea whats going on?

You absolutely need to run a return from the fitting where the fuel supply connects to the carbs back to the return fitting on the tank. Just install a fuel line tee.

Otherwise the pump pressure will overcome the needles and you'll have serious problems. We discussed that several pages back.

edit...the pump doesn't stop pumping...ever. On an FI system the ecu controls the time the pump runs. You have no ecu.

[memper]

Ah yes. I understand now. I might be able to just use the Y fitting thats down there now. Ugh. Im off now to drain the tank...

[MendoDave]

Thats what I was thinking.

What tells the pump to stop pumping? Does it get a sense when the float chambers are full and stops pumping? I ask because I turned the key and let it sit that way for 30 seconds and the pump never shut off. I thought pumps ran for a sec when the ignition was turned on but then it stops. And only come on when necessary. Do I have the wrong understanding? (Highly likely)

I don't think its that sophisticated. On most cars pumps run when needed. On one of my GM cars the pump would run when the ignition was turned on, but stop after 2 seconds if there was no distributor pulse sent to the ECU.

The fuel ran in a loop past the throttle body injector and the injector took that fuel pressure supply with injector "On" time as required.
But basically the fuel ran in a continuous loop from the pump back to the tank.

Ive never paid that much attention to motorcycle electric pump systems except for the pump on my VFR that used breaker points to turn the pump on and off. I don't know whats wrong with gravity feed systems for carbed bikes. I had several that used that system with very little problem.

[ducpainter]

Ah yes. I understand now. I might be able to just use the Y fitting thats down there now. Ugh. Im off now to drain the tank...

There is a fitting on the cap holder that connects to the small tube inside your tank. That is to drain water from the cap area.

I don't think its that sophisticated. On most cars pumps run when needed. On one of my GM cars the pump would run when the ignition was turned on, but stop after 2 seconds if there was no distributor pulse sent to the ECU.

The fuel ran in a loop past the throttle body injector and the injector took that fuel pressure supply with injector "On" time as required.
But basically the fuel ran in a continuous loop from the pump back to the tank.

Ive never paid that much attention to motorcycle electric pump systems except for the pump on my VFR that used breaker points to turn the pump on and off. I don't know whats wrong with gravity feed systems for carbed bikes. I had several that used that system with very little problem.

Gravity works as long as the fuel level is above the fuel feed on the carbs. On a Monster tank there is a bunch of fuel below the fuel inlet on the carbs.

[memper]

Yes. I have the beveled filler cap nipple going to the drain outlet. The other filler cap nipple is connected to the brass return line (internally).
Outside the tank, ot knowing what to do, i joined the drain and the return. I know now that it is the fuel outlet and the return that are to be joined.

[ducpainter]

Yes. I have the beveled filler cap nipple going to the drain outlet. The other filler cap nipple is connected to the brass return line (internally).
Outside the tank, ot knowing what to do, i joined the drain and the return. I know now that it is the fuel outlet and the return that are to be joined.

Because the old SS tank has a vent on top and doesn't use the second fitting you need to remove the cap holder and disconnect that other nipple from the return line or fuel will spray out of that fitting.

Get a 1/4" vacuum cap from Autozone and cap the fitting on the cap holder.

If you don't understand pm me and we can talk on the phone.

[memper]

I sent my number but I think I get what to do.
Right, the tank can vent from the breather hose on the top of the tank. And the brass return line inside...you just leave it alone, letting it point to the roof of the tank?

(sorry that fitting a damn gas tank and pump has taken 11 pages  )

[Duck-Stew]

Get a 1/4" vacuum cap from Autozone and cap the fitting on the cap holder.

I'm going to differ here.  The quality of vaccuum caps in the last 10 or so years has gone to total crap.  Use a piece of clear vynil tubing and put a bolt into the other end.  It'll last & last & last...

[memper]

Noted.
And to lighten the mood here is a fun pic:

[ducpainter]

I sent my number but I think I get what to do.
Right, the tank can vent from the breather hose on the top of the tank. And the brass return line inside...you just leave it alone, letting it point to the roof of the tank?

(sorry that fitting a damn gas tank and pump has taken 11 pages  )

Don't ever be sorry.

[memper]

 

[memper]

While I wait to fix the fuel routing mistake I will ask another electrical question.
I found really cool switches. Expensive but weather proof, stainless steel, black, and lit.
They rate at 12v 10a. Just fine for the kill and starter buttons. But the buttons I'm looking at (PlasmaGlow) have a small LED ring light for when the switch is activated. 7.5a would cook the LEDs in a second.
I called them but no answer to see if the switches ha a built in resistor. I'm guessing no.
Considering my set up, what size resistor might I need for the two start switches?

[ducpainter]

I doubt the led carries any of the load.

I'd have to see a switch diagram to be sure.