Why is my unkls banshee bakfireing???

my unkl has a high matenance banshee ( runs cam 2 and bean oil thru it it has upgraded jets and power core 2 exaust) we were out ridein sunday he had to go get his truck to jump my 4 wheeler and he told me to bring em arround the cornner so i did a cupple donuts /w his and i parked it he came back when he started it it was bakfireing and ran a little hotter than ushuall we cheked the spark pluggs 1 was golden brown and 1 was black we changed the black 1 rode it 4 a min and cheked them agian and they were both golden brown and still bakfireing do you think i blew it up blew a ring or maby spark probs? we were in some deep watter some mudd and yes it only smokes out of 1 pipe and do u no the cheepist way out of it?