yamoto 50 when running battery is dead within 5-10 mins. what charges the battery and how do i fix it?

 

could be the stater or voltage regulator.

 

Yes, or wiring problems.

Bigbucksforme: The battery is charged by spinning magnets mounted in the rotating flywheel past coils of wire mounted stationary in the stator. This generates an AC voltage. The voltage regulator changes this AC voltage to DC and limits it to the proper voltage and current to keep the battery charged and run any installed accesories such as lights.

I'm not familiar with your yamoto 50cc engine. How many wires are on you voltage regulator and what color are they? The next step will be to determine which are the stator output wires and measure the AC voltage coming from them. That will isolate whether the stator (and associated wiring) is not working or the voltage regulator is not working.

Are you sure your replacement battery is good? Was it fully charged? To discharge a fully charged 7 amp hour battery in 10 minutes would take a 35 amp continuous load. That's a rather hefty draw. Whatever was drawing level of current that would have to be getting very hot (nearly 400 watts!). More likely your battery was not charged, or it too is bad. Just raising the possibility...