[Eye_m_no_angel]

I want to find the cause of it not being able to crank up as well.

That's where you start.

Check to see if you have an engine and drive train that is even capable of being started and running before you start fixing other stuff. If your engine needs major repairs, and the cost exceeds the value of the bike, you'd be wasting sweat and coins if you work on fixing the brakes first.