No Fuel?

[Guest]

So I was going to begin testing tonight on my '82 GS750E, because I have recently done a lot of maintenance and fixing to it. I rebuilt the carbs with new o-rings, float bowl gaskets, Dynojet Stage 1 kit. Performed a valve adjustment with new valve cover gasket, installed a used airbox (the boots are good) with a K&N filter, as it previously had individual pods. I also replaced the breather cover gasket. I was trying to get it running, but it wasn't working. The starter was turning over, it has spark (also new spark plugs), and I don't think it's taking the fuel. I have a gas can strapped on top with the fuel line running into it. So I tried to pour some fuel into the line to get fuel into the float bowls since it had been rebuilt and completely dry, and after some more testing with that, it started to do it's thumping/combustion. It sounded so close, but unfortunately after trying to crank it over so much the battery was pretty much dead. So now it sits on the trickle charger, and I will have to try again tomorrow. This is frustrating because I finally am at the last phase to get her running and tuned. I was going to do a carb sync and adjust the fuel mixture tonight. Does this sound like a normal thing on it's first attempt at running after doing all that maintenance? Or is it not sucking up the fuel? I'm not sure, but I want to be able to do this testing, so if it's something I need to fix beforehand I want to know.

[Crankthat]

Probably just not able to suck it out of the fuel can.
Most of us make a fuel IV.
I made one out of a water bottle.
Cut out the bottom of bottle and drilled through the cap.
Inserted hose through the cap and sealed.
Hung bottle above bike and added some fuel insuring fuel only traveled inside hose as opposed to outside.


Clean and dry bottle first.
Do not leave fuel in bottle when done.
When you disconnect line there will be fuel in it.
Do not set yourself, dad or workshop on fire.


The tank sits above the carbs as there is not a fuel pump on the bike.
The carbs control a bladder inside the petcock.
The carbs do not have much power to suck the fuel up the hose.
The bottle will need to vent and is easier to fill with the bottom that is now upside down cut off.

If this will not work get back to us.

[Steve]

It's also possible that you are getting fuel to the carbs, but the throttle is not open far enough to let it through.

You should be using the "choke", hopefully you are doing it correctly.

Apply the "choke".
Turn the key ON.
Pull the clutch lever.
Press the starter button.

Did you notice that I never said "twist the throttle"? That's because YOU DON'T touch the throttle while using the "choke".

If it starts on "choke", modulate your engine speed by tapering off on the "choke" to keep engine speed down. If the engine dies when you take the "choke" off, turn the idle speed screw in a bit and try again.

.

[Anthony]

Both of these ideas make sense. I was using the throttle with the choke on, so I was doing that wrong. I'll make sure to so it properly tonight. Also, I didn't pull in the clutch because my safety switch is bypassed, does that make a difference?

[Steve]

Both of these ideas make sense. I was using the throttle with the choke on, so I was doing that wrong. I'll make sure to so it properly tonight. Also, I didn't pull in the clutch because my safety switch is bypassed, does that make a difference?

As long as you KNOW it's in neutral, no problem. Many (most?) of us don't like that "safety" switch and bypass it, but we can't assume that everyone else has, so we continue to say "pull the clutch".

The "choke" system on these bikes does not actually choke off the intake, like it did on early cars, it is an enrichener circuit that relys on the high vacuum of a CLOSED throttle to pull air and fuel through the separate passages. Open the throttle even a little bit, you will lose that high vacuum and the engine will be trying to start on the 'normal' circuits, which are too lean for a cold start.

By the way, what setting have you chosen for your pilot screws? About the only thing that can be guaranteed is that the stock setting was too lean, and could have been anywhere from 1 1/2 to 2 turns out from lightly-seated. If you turn them out to 3 turns as a starting point, you will provide a richer mixture, which is exactly what the bike needs to start right now, so you can get it fine-tuned.

.

[Missile99]

As long as you KNOW it's in neutral, no problem. Many (most?) of us don't like that "safety" switch and bypass it, but we can't assume that everyone else has, so we continue to say "pull the clutch".


The "choke" system on these bikes does not actually choke off the intake, like it did on early cars, it is an enrichener circuit that relys on the high vacuum of a CLOSED throttle to pull air and fuel through the separate passages. Open the throttle even a little bit, you will lose that high vacuum and the engine will be trying to start on the 'normal' circuits, which are too lean for a cold start.


By the way, what setting have you chosen for your pilot screws? About the only thing that can be guaranteed is that the stock setting was too lean, and could have been anywhere from 1 1/2 to 2 turns out from lightly-seated. If you turn them out to 3 turns as a starting point, you will provide a richer mixture, which is exactly what the bike needs to start right now, so you can get it fine-tuned.


.

Whoa Steve, that's got to be the best explanation for the "choke" system of these bikes that I've heard.

Anthony: If it's still not starting after your next attempt, check to see if the plugs are wet with fuel.

[Crankthat]

Both of these ideas make sense. I was using the throttle with the choke on, so I was doing that wrong. I'll make sure to so it properly tonight. Also, I didn't pull in the clutch because my safety switch is bypassed, does that make a difference?

My clutch circuit is bypassed also.
After 2-3 years I still pull in the lever.
Some habits.....

[eil]

Both of these ideas make sense. I was using the throttle with the choke on, so I was doing that wrong. I'll make sure to so it properly tonight. Also, I didn't pull in the clutch because my safety switch is bypassed, does that make a difference?

No, but when you're not working on the bike, pulling in the clutch while starting is a good habit to have. There is no neutral interlock (with good reason) and many people who have bypassed the clutch interlock switch out of convenience have had... shall we say mishaps... because they got used to not pulling in the clutch when hitting the starter button. Which is usually fine except that one time they don't realize the bike is not in neutral.

I got to see this in person, once. An MSF instructor dropped a bike this way.

[Anthony]

As long as you KNOW it's in neutral, no problem. Many (most?) of us don't like that "safety" switch and bypass it, but we can't assume that everyone else has, so we continue to say "pull the clutch".

The "choke" system on these bikes does not actually choke off the intake, like it did on early cars, it is an enrichener circuit that relys on the high vacuum of a CLOSED throttle to pull air and fuel through the separate passages. Open the throttle even a little bit, you will lose that high vacuum and the engine will be trying to start on the 'normal' circuits, which are too lean for a cold start.

By the way, what setting have you chosen for your pilot screws? About the only thing that can be guaranteed is that the stock setting was too lean, and could have been anywhere from 1 1/2 to 2 turns out from lightly-seated. If you turn them out to 3 turns as a starting point, you will provide a richer mixture, which is exactly what the bike needs to start right now, so you can get it fine-tuned.

.

I think the pilot jets are at 2 1/2 from lightly seated, but I'm not sure. I really hope I don't have to mess with them because I don't want to have to take the carbs off and on with an airbox, as that takes like an hour each time. Is there anyway to adjust them without taking the carbs off?

[bcvickers]

I'm nearly 100% positive that you didn't get much if any fuel into the carbs themselves unless you started a siphon in your fuel line. To restate what was said above, there is no fuel pump on our bikes and the carbs must be gravity fed from some sort IV bottle scenario when the fuel tank is not mounted. My personal setup is to use the gas tank off an old riding mower that has a petcock on the bottom. I (securely) suspend it from a rafter and hook up a good bit of fuel line, I prefer clear or at least see-through so that I know for a fact that fuel is flowing.

[Anthony]

I'm nearly 100% positive that you didn't get much if any fuel into the carbs themselves unless you started a siphon in your fuel line. To restate what was said above, there is no fuel pump on our bikes and the carbs must be gravity fed from some sort IV bottle scenario when the fuel tank is not mounted. My personal setup is to use the gas tank off an old riding mower that has a petcock on the bottom. I (securely) suspend it from a rafter and hook up a good bit of fuel line, I prefer clear or at least see-through so that I know for a fact that fuel is flowing.

That makes sense, and I must of not fully thought things through with fuel setup. I will make a IV bottle for the fuel and make sure gravity is feeding the fuel into the carbs, I just was also afraid of the float bowls getting flooded and fuel going into the airbox.

[eil]

That makes sense, and I must of not fully thought things through with fuel setup. I will make a IV bottle for the fuel and make sure gravity is feeding the fuel into the carbs, I just was also afraid of the float bowls getting flooded and fuel going into the airbox.

You can also borrow the gas tank off a lawn mower or weed whacker. Just make sure it has a vented cap and is held up higher than the cars.

If the fuel valves are working correctly in the carbs, the float bowls should not overfill. But if they do, the fuel will go into the engine.

[Anthony]

You can also borrow the gas tank off a lawn mower or weed whacker. Just make sure it has a vented cap and is held up higher than the cars.

If the fuel valves are working correctly in the carbs, the float bowls should not overfill. But if they do, the fuel will go into the engine.

Well that's what I originally thought, but when I first got the bike and we took the carb bottoms off to clean the mains and re-installed (this is when it had pod filters), gas came out the filters and made a mess. But since then I've done a complete re-build as stated above

[Steve]

I think the pilot jets are at 2 1/2 from lightly seated, but I'm not sure. I really hope I don't have to mess with them because I don't want to have to take the carbs off and on with an airbox, as that takes like an hour each time. Is there anyway to adjust them without taking the carbs off?

Well, the first thing you need to do is to learn the terminology.

The pilot JETS are down in the float bowl, next to the main jet and should be firmly snugged into place at all time.

The pilot SCREWS are the only real adjustment on the carbs. They are visible while the carbs are installed on the bike. They are on top of the output throat of the carbs and can be adjusted by merely removing the gas tank. THOSE are the ones that need to start about 3 turns or so out from lightly-seated.

Take the carbs off one final time, tighten those JETS back into place. Put the carbs back on, check the settings on the SCREWS.

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[Anthony]

Ahhh, I see. Now that you say that I definitely had the pilot JETS snug. I was also talking about the pilot SCREWS which I did put at 2 1/2 from lightly seated. I confused myself, I apologize haha