Isn't this a case of survivorship bias, like when they took a statistical view of all the areas where WWII airplanes got hit by bullets and they wanted to increase the armour, but a statistician told them to armour the parts where no bullets had hit... because they only surveyed planes that came back whole and the ones that didn't come back had likely been hit in parts of the plane they didn't add to the survey.
No, survivorship bias would be looking at motorcycle injuries by only talking to motorcycle injury survivors. Your conclusion would be that motorcycle injuries only result in minor small damage like skin abrasion, broken fingers, etc. Your conclusion would be that brain injuries basically never happen because all the survivors you spoke to were fine.
If you're looking at casualties from motorcycle incidents, you by definition are not looking at survivors.