i have a 69 shovelhead with 3 13/16" aluminum barrels,SS model B carb,and its backfiring bad and it hardly runs. ive rode since i was 16 and only had HD but this is my first cone motor, i know a little about them but not alot. does anyone have any ideas what it might be? im thinking it might be ignition but what?

Hi weedsprayer,
Welcome to the forum. You may have a intake leak, could be in the carb, mainifold etc. I have even seen backfires with an exhaust leak too. IF it barely runs might be the leak as it is not getting enough fuel to run. Could also be a valve problem which could be anywhere from the cams to the heads. One thing that you can try and be careful is to spray a little starting fluid in the carb while it is running, be very careful that it doesn't backfire up through the carb. If the engine speeds up you probably have a leak and if it doesn't then you need to go deeper. Hope this helps, I am not a professional so you may want to get a second opinion before digging really deep. Good luck

Welcome aboard!!
I can back fire my bike by shutting the switch off and gunning the throttle and then flip the switch back on and BAM!!
So, I'd go with the ignition and a bad connection or broken wire somewhere along the way.
RK

weedsprayer,

you ever get that problem worked out?