My bike gave up

[Iggy76]

The deal with Petcocks, is 3 stages. Normal or Run draws fuel from the top of the inner tank fuel tube. Reserve draws it from the bottom of the tube, both require a vacuum source to open the fuel valve on the bottom, this valve prevents the carbs from flooding should the float valves leak a little in the carbs. Prime is the system that pushes open the petcock valve and lets fuel into the carb without a vacuum source. I suspect the vacuum hose might have a crack on it or fallen off. Try running it on prime to see if the petcock is an issue.

This is entirely correct, keep in mind: in prime (if the bike is equipped) it draws from the lower "reserve" pickup. Meaning if you drive around in the prime position and "run low" on gas, you are actually completely empty and stuck.

My guess: out of fuel and the continued cranking on the side of the road has diminished the battery...

 

[Sora]

Update: Grabbed some gas while filling the car, put in enough to fill the tank about halfway.

Turned it on, let it warm up for a few minutes. Seems to work mostly okay, hurray! I was going to ride it around the block to test it, but I live at the top of a hill and it's raining, and if something DOES go wrong, it's going to be a very very slow push back up the hill.

So I thought I'd test what I could: petcock set to "on", in neutral. Increased the throttle very slowly and steadily. It crept up to 2k rpm, then dipped a little before it kept going up. Alternatively if I just increased it to 2k and stopped, then increased more it took over a second before the engine responded. Is this normal? This only happened if I was very slow on the throttle, if I just rolled hard on it the rpms zoomed up.