Bike stalls at idle

[Bethinkin]

My '78 xs650 special likes to keep me on my toes. Lately it will stall while I am sitting idle at a stop light, if I don't let it warm up long enough. I can get it started just fine, using the choke on a cold start. It will idle in my driveway for 5 mins without an issue, but sometimes it will die randomly. That usually happens on cold mornings. The stalling at red lights only happens when I kick it over and go. Doesn't matter if I have been riding it, stopped at a store for a few mins and then go back out.

This morning I let it warm up, and rode to work without an issue. At lunch I ran to the store, got back on the bike and started back to my office where it stalled at two different lights. If I keep giving a little gas it seems to be fine. I'm going to start with the battery connectors, but since the lights all stay on, I'm thinking those are good. I'm just looking for ideas right now. Ignition, regulator, alternator, etc. I should say that I have just reworked this bike, so the carbs were just recleaned, gaps redone, battery fully charge, etc. Any ideas on where to take a look are appreciated.

 

[Bethinkin]

May be useful to say that I'm still running the points ignition. Wondering if I need to go with the Pamco.

 

[650Skull]

Maybe your idle is a bit low, 1200 is around the mark. Does it help if you adjust the idle screw a bit

 

[Brassneck]

Perhaps charging is low? at idle, the bike is pretty much drawing power direct from the battery. A weak battery and charging minimally (like 5 min. runs here and there) doesn't put the battery back up to full charge.

I'd check your power, clean connections, etc...and up your idle a bit, see if that helps.

 

[Bethinkin]

Maybe your idle is a bit low, 1200 is around the mark. Does it help if you adjust the idle screw a bit

That was my first thought as well. I was at 1200, but I even upped it to 1500 to see...no dice. When it's idling it seems to be running great. It doesn't sputter or run rough at all.

I called a mechanic and he suggested checking the air flow on the carbs and the ignition.

 

[nj1639]

I'd bench synch the carbs, set the mixture screws to spec and double check the float heights while the carbs are off.