Looking for ideas what may be causing my '73 CB500 to stall for a quick second when starting in 1st gear or 2 seconds after shifting into second gear? Acts like the key switch was turned off for just a milla second. It's a new(used) bike so I haven't made it to third or fourth gear to see if it occurs in the othrr gears. I'm thinking more on electrical side? Any thoughts?

 

im thinking more on the fuel side, did the bike sit for a while before you bought it? if so, pull the carbs and check the floats to see if they are going back into place when the fuel is turned on. give them a good cleaning

drain the gas if you havent already and put fresh in.

check for blocked passages in the fuel cap venting.

the petcock screen may also be clogged from the old gas if it sat for a while. the screen is inside the fuel tank so i believe the tank needs to be removed and the petcock removed for cleaning. try not to break it.