Any idea on this... I have a Zenith carb on this 1340cc motor. That was not stock was it? Anyway it after it starts cold fine, I ride it for say 5 miles then stop. when I restart it runs bad, misses, smokes and backfires out of the carb. Took off the air cleaner and black soot covered the carb. Wiped the soot off and found the Zenith trademark. the manual shows a cv carb! This one has two large adjustment screws and one smaller one on the top of the carb. Could the rough running be an adjustment problem? What should the plugs look like? Appreciate any and all help...

 

is this the way you got it?did you change anything?could be timing.could be fouled plugs or leaky manifold.it should have a cv carb.i hated those zenith carbs

 

sounds like fuel is leaking into the cylinders after shut down next time shut petcock off before you shut down and see if you have the same problem on restart possibly carb is bleedding into cylinders