left side firing hesitation

[backyard mechanic]

78 xs650, bs34 carbs with pods and jetted. The problem I having is when I start it the left side doesn't always fire right away, with some throttle and lil choke the left side will slowly start to fire after warming up with the occassional backfire out the exhaust. Once warmed up it seems to go away. I have new plugs and gas and have replaced the carb boots. I checked the plugs after my last ride and the right side plugs looks perfect, the left side plug seams to be running rich. Could this be float adjustment or valves etc?

Thanks

 

[IOMC Hardtail]

Mine does the exact same thing. I thought it was running rich on the left side cause the plug would always be charcoal. Then I looked in the left side exhaust pipe and noticed it was covered in oil inside. Come to find out I have a head gasket leak on the left side and the hesitation on firing on the left side is due to the oil seeping in the cylinder. Once it burns off, about 5 seconds, it runs fine. Just a little bit of smoke out of that pipe. Planning on a rebuild this winter.

 

[backyard mechanic]

Hey IOMC hardtail, that would makes sense when the bike is cold. I appreciate you letting me know about the head gasket leaking, I have the same thing with seeping oil out of the head gasket.