Hey. I just got out with my 86 1100 XL last night and here's the problem. I started up the bike, it warmed up good. I got on it and it ran good for about 4-5 miles, then it started to backfire and cough? pulled over and the thing idled good?? as soon as I turned around to go home, it backfired all the way home. It only happened when I got on the throttle. Could it be I have bad gas? Or using to high of octane? I can't remeber what it is, I think its 87 octane.
i dont think it's the octane, could be bad gas but id have someone check the coil, plugs and wires. also if the bike has points, they go bad without warning, if it does have points, look in to a different ignition system.
You need to run at least 91 octane gas. The single hose pumps may still have a lower octane in the feed line so what I do is fill up when I'm near reserve so that small amount of lower octane will dilute with the higher octane. I do have an old style gas station at the corner that still uses the three hose system.