Hey y'all, I registered here so I could get some advice on what to do about my Intruder 750. Like the title says, it backfires so much it almost blew out a baffle. The thing is, it only does it when it's in gear. I start it normally, no problems there. It idles fine and I somewhat adjusted the A/F ratio as it was running rich.

I have been tuning it up becuase it sat for a while when my friend owned it. I did plugs and coils, carburetor clean and rebuild, oil change, a new fuel pump and starter relay. I'm new to V-twin motors as I've only had experience with inline 4 sport bikes. Any help would be appreciated