UPDATE!
I took the ICE motorcycle to Dyno 250i and the rpm was being picked up successfully from the hall effect clamp pickup. BUT,
My ideal square wave generated from TONE method starting from 30Hz to 30Khz I tested didnt work, I also tested at various voltage levels including 3v, 5v, 12v, 9v but the output from Arduino wasn't able to mimic the RPM line on the motorcycle.