I'm doing some research on the Honda CRF450. This is a single-cylinder engine. I'm interested in the fuel-injected models (not the older carbureted versions).
As far as I can tell, this engine doesn't have a camshaft position sensor, so there's no way to tell which stroke the engine is in. This means that the bike can only use the crankshaft position to decide when to inject fuel and when to spark, and it can't tell the difference between the compression stroke and the exhaust stroke.
Does this bike inject fuel AND spark during the exhaust stroke? I understand wasted spark systems, but I thought those only worked because there's no fuel during the exhaust stroke. Is there any way for this bike to avoid injecting fuel outside of the compression stroke, and if not, why is it okay for the bike to use "wasted combustion" with both fuel and spark firing at the wrong time?