I don't have any issues carrying appendix on a sportbike or dual sport bike.
One more thing that is more important than everything in that no so great artical is that you should be really thinking about a crash and where the placement of your gun is when you hit the asphalt maybe from a low side or worse, a highside. DO NOT carry around the backside IWB! If you land on hit the road with your gun and nail your lower vertebrae on your spine, you can be permanently paralyzed. Many squids on sport bikes and middle aged asshole hog riders don't wear next to any protective gear as it is, so for them, it doesn't really matter as they're bound to win a darwin award anyways. For those that aren't dressed to try to be cool and wear proper gear, (often much more experienced) a shoulder holster and pocket carry is probably the best. I still prefer appendix carry because your groin area is unlikely to cause further problems in a crash if you're sliding or in a tumble, and if you're wearing gloves it's going to be easier not to have to unzip jackets or pockets and reach around to grab a hold of the pistols grip. I wouldn't advise that any smart person wears IWB off the hip either. Think about a crash, even a slow speed crash...