Hey guys, first post here. I'm looking to run a small electrical device on my motorcycle. I have 12v ac power coming from the stator that I can tap directly into. I need 12v dc to run the device. What is needed to convert it in to dc power?

 

Any motorcycle has a 12V DC system that runs all of it's electrical components. I can't understand what you are asking.

 

It's a dirtbike, do it dosnt have any lights. But they use the same motor in a scooter in Japan, so the stator is already wound. I know which wire to tap into for running a 12v ac head light, but need to convert it to dc to run a rev limiter.

 

Full wave bridge rectifier (4 diodes) + "large" electrolytic capacitor + voltage regulator such as 7812.

You may not need the regulator. It depends on the requirements of your circuit. Rectified 12VAC will give well over 12VDC, maybe 16V or more. You'll lose 1.4V across the diodes of the rectifier, and about 3 more volts across a regulator. If you don't need the regulator to clean up the power, and you just need to reduce voltage, you can use extra diodes if you just need to shave off a volt or two.