Throttle kills engine

[giganticflying]

The gas is brand new. I de-rusted my gas tank with apple cider vinegar and screws, rinsed with water and baking soda, then rinsed with fresh gas, drained, and filled with fresh gas.

I don't know the voltage to my coils. I'll buy a volt or multimeter on Monday when I go to Harbor Freight. There is visible spark with all the coils, but I'll try it tomorrow in with the garage light off to see if any are weaker than the others.

The fuel screws I set to about 5/8 of a turn since I kept reading either 3/4 or a full turn. I did remove the fuel screws (and all other parts) before dipping the carb bodies.

Now that you mention it, though, I did forget to adjust the float height.

[OldVet66]

I think that is your next step, you have something going on that doesn't make any sense if the carburetors were rebuilt properly. Check your manual, but I believe they are set at 24mm then check them with a sight tube as the bowls fill and then running. The level should be in the middle of the float bowl edge where they screw to the carburetor, that should keep the level just below the gasket. When you adjust the tab on the float it is helpful to find a miniature set of channel lock style pliers to hold the tab while you bend it ever so slightly, measure height again and repeat until they are dead on the measurement. The baby channel locks will keep you from twisting the tab.

[giganticflying]

I'll give that a shot, but is there anything else it could be? I mentioned before that the plugs are ash black. Any thoughts on that?

[OldVet66]

Could be too much fuel, also float related. Lightly seat your pilot fuel screws and tell me if the tips stick up into the carburetor throats. If they do, the screws have expanded the seats by being screwed in too tight. This changes the adjustment game because you have to compensate for the damage done previously to emulate proper settings. I would set the pilot fuel screws at about 3/4 out to begin and the air screws to 1 1/2 out. It won't be right but it should start with choke if everything is clean, bench synced properly and the float heights where they should be. Then the tuning fun begins.

[KEITH KRAUSE]

For basic starting purposes, adjust the side air screws to 1 3/4 turns out from lightly seated and adjust the pilot fuel screws to 3/4 turn from lightly seated. For what I assume is a bike with stock intake/exhaust, those adjustments are close enough that any stalling issues cannot be attributed to them. Your model should idle well at 1,000 to 1,100 rpm's. Turning the idle up higher causes it's own problems.
If you didn't clean the pilot circuit 100% then you'll have hard starting and stall easily. If you dis-assembled the slide/jet needle assemblies, then you must carefully bench synch the slides or starting will be difficult regardless of what else is checked. Did you bench synch? Did you re-assemble the jet needle assemblies correctly, including the positioning of the nylon jet needle e-clip spacers? Float heights should be set right in the middle of the factory range (.95"). Float bowl vent lines routed under the seat and no kinks.
NGK B8ES plugs, properly gapped? Do you see all solid bluish sparks when you turn the engine? Could be lots of things.

[Big T]

Your plugs are black because you're using the choke

[Sci85]

Nah, choking the plugs turns them purple. You likely have the African American plugs. You want the Caucasian version. Specify the Cali tip for that just right tan color.

[giganticflying]

Ok, so today when I got to the garage I set the air screws and the idle screw back to default turns and it started up with choke! I let it warm up for about 45 secs and when I took the choke off it died. I after a couple more tries I was able to get it to idle at around 2500-3000. When I took it off choke, it dropped down to about 1200, stayed there for a while, then died. I started it up again without choke and by revving the throttle a little I got it to stay on. After a while, I decided to take it for a ride and it drove ok!

Here's the deal, though. I noticed that exhaust pipes #3 and #4 at the engine were not as hot as the others when i first started it up. They eventually both got up roughly the same temp (my palm at a distance is not a good measurement, I know) but there is some occasional burbling out of the exhaust pipe they're connected too. I gave a small turn on the air screws for that side and it seemed to help a little, but when ride it, throttling is a little shaky, especially in first gear. Any recommendations? I'm going to purchase a manometer soon, and try to do a plug test later this week so I can fine tune the fuel screws. I did previously do bench sync. My buddy is bringing me a volt meter tomorrow just in case its something to do with a low spark or something.

[OldVet66]

In the beginning, I had similar issues and solved them by switching to a Dyna-S ignition and 8mm suppression wires. I never looked back, there was quite a positive difference and I would probably still be chasing my tail if I hadn't made the change. Eliminating all possible ignition problems is a huge step forward.

[giganticflying]

I've already ordered new points and condensers from ebay so those should be arriving soon.

I am happy to say that I am able to ride it around now! Just I'm just not going to do it often until I can figure out why the acceleration is shaky. Currently, it idles around 1,500 after its warm.

[KEITH KRAUSE]

Ok, so today when I got to the garage I set the air screws and the idle screw back to default turns and it started up with choke! I let it warm up for about 45 secs and when I took the choke off it died. I after a couple more tries I was able to get it to idle at around 2500-3000. When I took it off choke, it dropped down to about 1200, stayed there for a while, then died. I started it up again without choke and by revving the throttle a little I got it to stay on. After a while, I decided to take it for a ride and it drove ok!

What you describe here is classic symptoms of a dirty and/or varnished pilot circuit with the emphathis on VARNISHED. Your pilot circuit is NOT delivering adequate fuel, that's why when it's cold/warming up, it runs only with choke. Once it reaches operating temperature the overall "conditions" tend to richen and combustion improves though I can tell you it's not running well. Once it reaches operating temperature the improvement has you thinking it's OK but it's still not getting enough fuel. The carbs are NOT cleaned correctly regardless of what your efforts have been.
It's also true as others have said, that this bike has multiple issues. The stock points/condenser system is weak and must be well maintained to work properly. New points/condenser isn't half of it. Proper points gap/alignment/dwell must be set, then you adjust the advance properly. Check the coils for adequate primary/secondary voltage. Check reg/rec' voltages. All the electrical things just mentioned depends on a good battery.
I've read enough here that it's clear you have multiple issues, some requiring attention more than others maybe, but multiple issues all the same.
It's an old bike. It takes patience and money and effort to get it running well. Short cuts or partial maintenance, for whatever reason(s), will never achieve good results. It's just the way it is with old stuff.