GS750L not running on cyl. 2 and 4

[jmacneil2003]

I just drug home a new project...... 1981 GS750L. The previous owner told me the bike has an intermittant spark problem. The first thing i did was pull the coils, plugs and carbs. Cleaned the coil connections (ground), replaced the 4 plugs with new NGK plugs and dropped the bowls on the carbs. I pulled the main and pilot jets out of all the carbs and sprayed carb cleaner everywhere the straw would fit. The carbs looked fairly clean to start with; however, they have been worked on because the carb boots btween the carbs and airbox were not mated. I had to warm them up with a propane torch ever so slightly to get them soft enough to install. The bike is back together and seems to run fine for the first few minutes after starting. Once it starts to warm up it develops a hesitation. With the bike running I can pull off plug wires 2 and 4 and nothing happens. I swapped wires 1/4, and 2/3. Also switched the plugs around. The problem seems to stay with the cylinders. If I pull wires 1 or 3 the engine dies. Any ideas on where to go next?

[relic-rider]

I'm guessing most likely this is a carb problem. The needles and seats may be hanging up on those 2 cylinders and it isn't getting enough gas to run. It runs at start probably with the choke, but if you take off it dies. Or something in the idle circuit is plugged. I had a problem like this on #4 and it went away after I rebuilt the carbs with new needles and seats and pilot jets.

Dan

[jmacneil2003]

Thanks Dan, I pulled the plugs out and they were sooty. After doing some research on this site it turns out that I am headed for the "Stator Papers". I did some tests and it turns out the bike isn't charging properly. Go figure:? The old owner left me a duct tape suprise wrapped under where the left side cover goes. I'm thinking it must be the R/R. Gonna research it now.

[jmacneil2003]

I ran a direct ground from the R/R mounting plate to the battery and all is well. Running on all four but won't idle properly. I know that the boots are not sealed tightly to the airbox. Could this cause it not to idle right? I'm thinking about trying to silicone around each boot to the airbox to seal it up. Its gonna take more then a week for my new boots to come in. Any thoughts?