Im new at this so if i put things wrong thats why thanks.
I got this bike 2 yrs ago its a 1983 honda shadow vt750c , i got it with custom aftermarket pipes with 27k miles on it. the problems i am going around in circles with is the backfiring and getting the carbs tuned. about 2k miles ago i got he carbs rejetted thought that would get rid of the backfiring but it didnt only the thing it did it backfire more evenly more the same volume backfires, so when i had a mechanic do that he rebuilt what need to be done far as i know to the carbs and synced them, but when i got it back i found i was goin threw plugs and it was running rich as far as what i seen on the plugs. when i replaced the plugs i got rid of all the backfiring for about 100 miles and it came back and i went to the hottest plugs i can get which is 7 i believe, so i asked them about that and they said play with the mixture a little so i did, quarder turns at a time. when i think i got it right its a pain to start when its cold, ill turn the choke a quarder way up and it wont fire at all, but when i turn it off it will fire and run for a few rotations and shut down so i do it again but i help it, when it fires up again i crack the throttle and let it sit and idle but it idles ruff until i turn the choke on, and the only way to turn the choke on with out stall it is the rev it up a little and turn the choke on at the same time then its reving a little worming up from then on it runs good and all. but when i turn it the mixture down a little bit it fires up better on cold starts but its harder to start when its all wormed up i have to help it fire up with some throttle. i was told that the jets have been upgraded to a 44 mm and it was a 42 mm. i have been reading on these forum and seen similar but not the same. and i see it is famous for the backfiring but it would be great to fix it. if anybody can give me some hints or know whats goin on i would appreciate it alote.