Did the company give you injector specs showing they work?
Usually I'm messing around with carberated stuff and that's a common symptom of sitting. As the gas solidifies in the carb. Your gas injected so the next step is the pump. Your fuel sock and filter are likely clogged up. When you try revving the bikes rpms up it requires more gas which your not getting so it Boggs out and dies. That's where I would go next.
5 years is a long time even for gas with stabilizer in it.