I have a 2004 XL1200R with stock carb setup and V&H slip-ons with ~7500mi. It occasionally backfires (loud like gunshot) in higher gears usually going up hill. When it happens the engine light comes on, spedo and tach zero out, then spedo resumes and engine light goes out. Has only been happening for a couple of weeks. Any Ideas what is up?

 

Start by checking for any DTC's, (Diagnostic Trouble Codes), on your speedo.....There's a procedural write up on how to check for the codes in the DIY sticking at the top of the sporty page.

 

I checked, and there are no spedo error codes.

 

Sounds electrical to me ....ignition issue maybe?

 

Loose battery?

I'd start by checking all electrical connections from the battery to the coils/plugs and everywhere in between.