Here is an interesting part found at Monster Scooter Parts
This 2-stroke 4-pin rectifier (also sometimes known as a “voltage regulator”) is an excellent little piece of motorsports electronics that may just be the missing piece needed for your Yamaha project
30 Day Warranty Description

Here is an interesting part found at Monster Scooter Parts. This 2-stroke 4-pin rectifier (also sometimes known as a “voltage regulator”) is an excellent little piece of motorsports electronics that may just be the missing piece needed for your Yamaha project.
This 4-pin rectifier was originally made for the Yamaha SR150 lightweight street bikes, and the later Yamaha XJ600 Diversion/Seca series. In addition, this rectifier may be found on a number of Chinese-made Yamaha clones.
Please study the photos and the Specifications tab to see if you can use this rectifier on your bike or scooter. It may also be an excellent choice for a go-kart, ATV, or dirt bike. Specifications

Connector: 4-pin horizontal
Length: 3-3/8″
Width: 1-9/16″
Height: 1″
Distance between holes: 2-3/4″