Snowmobile rectifier question.?

[Monza Man]

I have a 1971 Arctic cat Lynx with a 292 single cylinder engine. I am going to put electric start on it. I have all of the wires, parts etc. for the job, except for the regulator/rectifier. I dont think it needs a regulator because it dosent have a regulator for the lights (the lighting coil dosent put out more than 16-17 volts, it dosent need a regulator). Does anybody know where to get a cheap, universal rectifier/diode and or a regulator/rectifier?

Thanks