Mine acted like it was out of gas yesterday. I started it put on my helmet and pulled onto the street and it started to stall.I hit the chock briefly and it was fine.I had riden it to work and it sat in the sun all day [heat index of 107] ran fine the rest of the way home and this morning. I'll see what it does after work.
It happened again yesterday after work. I can check all those things but what gets me is it only happens in the afternoon after sitting in the heat, never in the morning. It does make me think that it is either a petcock or vacuum problem. When I went to prime it took care of it, then when I switched back it would happen again. First I am going to check the vacuum lines and see if that is the culprit. Anybody ever take their petcock apart just for cleaning?I think it's a vacuum problem also but I'm thinking your slide in #2 is sticking because of varnish. A little carb cleaner in the air filter without the filter and engine running might cure it if the vacuum hose or petcock isn't the problem.
Everything worked okay last night. I think that the culprit was the dirty Air Filer. Not know exactly how the carbs work I would say that the clogged filter was preventing air flow which contributed to the lack of vacuum. I will keep an eye on it the next couple of days but I feel certain that it took care of the problemSince we haven't heard from you, it must be working fine. A clogged air filter will increase vacuum by restricting air flow. I don't know how that would only be a afternoon problem. Inquiring minds want to know!