Loud popping or barkfiring while running

i have a V twin motor . its a Ultima moyor 100ci, it was running fine and it act like it ran out of gas popping and back firing. put new gas in and still popping. i check for air leaks and cleaned the carb. still popping while running.
i don't think it the timing cause it starting, next step is pull intake and checking to see witch clinder is doing the popping. i think it is a stuck open value on intake on front . it a 2008 motor with maybe 15,000 miles. need help to figure this out before getting to far into the motor.

:roflmaooping out the carb or exhaust. Need more info?to help ya the boys on the forum ain't gotta crystal ball ya know!

Them ultimas got vavle seat problems they fall out of the valve seat pockets. Quite often. Or they bend push rods. After you get on them hard.

thanks for input, checked timing , still in time. it back firing though carb. i think now it is a stuck close exhust value. run compression check 150 psi.
what are the signs of a stuck value or bent push rod?

if its poping in the carb its gonna be on the intake side . if carb is not to lean . and compresion is equal on both cylinders . check spark secondary for problems . not primary ignition side! you verified timing . ignition or valve train timing wich one ?

it was on left side. pulled alum screw and veiwed mark on crane. not sure.
compression on both clinders was 150.

dose anyone know what manual i can get for this motor? ultima 100ci , it says on m.s.o. its a 2008, someone said they stop putting carbs on these in 2006.

then the heads are fine time too look some ware else for your problem if compresion is good valves are fine if it was a push rods or valve that was stuck cylinder pressure would not be equal !!!! if timing was out on crank compresion would suffer as well. look for a vacum leak or fuel and spark problem

thank you

your welcome

primary is the coils?
secondary is the points go?
on right side we pulled the cover where there was a round thing that had a light on it flashing red when try to start. he was moving the plate behind that and it made it hard to turn over then moved it back.could it be in there?
there a 30 amp fuse on side of battery, could that be part of it?