Throttle kills engine

[Guest]

Hey everyone, I thought I had an electrically issue, which you can follow the progress of here:

http://www.thegsresources.com/_forum/showthread.php?226294-After-lots-of-repair-(seemingly)-no-spark-or-starter-functionality

...but it turns out I just need to learn a few things about the starter system and the ignition. Now it appears I have a fuel issue. After tearing apart and cleaning/dipping the carbs, changing the motor/gear oil, replacing the spark plugs and cleaning the tank, I can get the bike to start up for the first time in four years. But! When I apply any throttle, it kills the engine. Is this a fuel/air screw adjustment situation? It idles at around 1500 to 2000 without choke. Going back into the garage tomorrow, hopefully with some good knowledge. Thanks in advance.

[mrbill5491]

Hey everyone, I thought I had an electrically issue, which you can follow the progress of here:

http://www.thegsresources.com/_forum/showthread.php?226294-After-lots-of-repair-(seemingly)-no-spark-or-starter-functionality

...but it turns out I just need to learn a few things about the starter system and the ignition. Now it appears I have a fuel issue. After tearing apart and cleaning/dipping the carbs, changing the motor/gear oil, replacing the spark plugs and cleaning the tank, I can get the bike to start up for the first time in four years. But! When I apply any throttle, it kills the engine. Is this a fuel/air screw adjustment situation? It idles at around 1500 to 2000 without choke. Going back into the garage tomorrow, hopefully with some good knowledge. Thanks in advance.

Do you have the air box and all that installed and buttoned up?

[giganticflying]

Going to do that tomorrow as well. The airbox is newly sealed and cleaned, I just figured that if the airbox is off and the slightest throttle is still killing it then there is still something wrong.

[Nessism]

http://www.thegsresources.com/_forum/showthread.php?t=171846

[giganticflying]

Whoops. I'll throw it on tomorrow. The other thing I forgot to note though is that the plugs look black when I pull them after idling for a while, which according to the manual indicates its rich rather than lean. I'll post updates tomorrow. Thanks everyone.

[giganticflying]

So I put the airbox back on. It starts up just fine (with choke. I even got it to kick start!), but only stays on for about 6-7 second before it stops again. It's not an abrupt stop, it just gradually dies over the last 3-4 seconds. Some have suggested to clean the carbs but I gave them an incredibly thorough cleaning a few weeks ago. Before I go back in there, does anyone have any other suggestions?

[giganticflying]

Also, the boots are nice and squishy with no cracks. I got new o-rings for the engine side. With my lack of knowledge in motorcycles, I can't really tell if this a lean issue or a flooding issue.

[Missile99]

Is your petcock in the on position when trying this? How much gas did you put in? If not much, turn to reserve. Otherwise, once started, put in prime to test fuel delivery. Don't leave it there if you turn it off though.

[giganticflying]

I've been trying to start it in prime and turning it to ON when I'm not working on it. I also have a new fuel line.

I started backing out the air screws on the outside of the carb and it seems to idle a little longer but still does the same thing. I'm at about 3.5 turns out with seems way too far.

[Katarat]

The filters on the factory petcocks can get plugged up over time too. Another thing to check if you don't get good gas flow in the prime position

[giganticflying]

The fuel hose I installed is clear and appears to be full all of the entire time. Sometimes there are small air bubbles so I imagine there is some kind of flow. Right before I left I got it to start up and idle without choke until I tried throttling after turning out the the pilot screws on the outside of the carbs.


How many turns should the idle screw be turned against the plate?

[Steve]

Some have suggested to clean the carbs but I gave them an incredibly thorough cleaning a few weeks ago.

Please describe your "incredibly thorough cleaning".

Was it anything like this?

http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf

If not, I think you know what is next on your agenda.

Every shortcut you take is just one more opportunity to do it right.

.

[giganticflying]

It was exactly that, except for the manometer portion, since I don't have one.

[Missile99]

Okay. Your carbs are fully cleaned, the air box is sealed and you have no air leaks. The mixture screws at 3.5 turns out should have caused a really lean idle mixture. Idling without choke is always good. I'd like to stick with simple questions before you tear your carbs open again. Is this fresh gas or stuff that's been sitting in a gas can for mowing lawns? It doesn't take long for this newer gas to go sour. What is the primary voltage to your coils? Is your spark decent looking? I looked at your other thread. The way I check is to lay all the plugs stuck in the boot on the head. Check in a darker area. Turn the key on and turn the engine by hand.

[OldVet66]

I haven't heard any mention of pilot fuel screw adjustment, just air, could it be that you missed those when you cleaned the carburetors. If so, they are due for another tear down and 24 hr. soak in carburetor dip with the pilot fuel screws removed. Did you bother to adjust the floats?